IO

Class

Expect library adds the IO instance method expect, which does similar act to tcl’s expect extension.

In order to use this method, you must require expect:

require 'expect'

Please see expect for usage.

The IO class is the basis for all input and output in Ruby. An I/O stream may be duplexed (that is, bidirectional), and so may use more than one native operating system stream.

Many of the examples in this section use the File class, the only standard subclass of IO. The two classes are closely associated. Like the File class, the Socket library subclasses from IO (such as TCPSocket or UDPSocket).

The Kernel#open method can create an IO (or File) object for these types of arguments:

A plain string represents a filename suitable for the underlying operating system.
A string starting with "|" indicates a subprocess. The remainder of the string following the "|" is invoked as a process with appropriate input/output channels connected to it.
A string equal to "|-" will create another Ruby instance as a subprocess.

The IO may be opened with different file modes (read-only, write-only) and encodings for proper conversion. See IO.new for these options. See Kernel#open for details of the various command formats described above.

IO.popen, the Open3 library, or Process#spawn may also be used to communicate with subprocesses through an IO.

Ruby will convert pathnames between different operating system conventions if possible. For instance, on a Windows system the filename "/gumby/ruby/test.rb" will be opened as "\gumby\ruby\test.rb". When specifying a Windows-style filename in a Ruby string, remember to escape the backslashes:

"C:\\gumby\\ruby\\test.rb"

Our examples here will use the Unix-style forward slashes; File::ALT_SEPARATOR can be used to get the platform-specific separator character.

The global constant ARGF (also accessible as $<) provides an IO-like stream which allows access to all files mentioned on the command line (or STDIN if no files are mentioned). ARGF#path and its alias ARGF#filename are provided to access the name of the file currently being read.

io/console

The io/console extension provides methods for interacting with the console. The console can be accessed from IO.console or the standard input/output/error IO objects.

Requiring io/console adds the following methods:

Example:

require 'io/console'
rows, columns = $stdout.winsize
puts "Your screen is #{columns} wide and #{rows} tall"

Example Files

Many examples here use these filenames and their corresponding files:

t.txt: A text-only file that is assumed to exist via:

text = <<~EOT
  This is line one.
  This is the second line.
  This is the third line.
EOT
File.write('t.txt', text)

t.dat: A data file that is assumed to exist via:

data = "\u9990\u9991\u9992\u9993\u9994"
f = File.open('t.dat', 'wb:UTF-16')
f.write(data)
f.close

t.rus: A Russian-language text file that is assumed to exist via:
```
File.write('t.rus', "\u{442 435 441 442}")
```
t.tmp: A file that is assumed not to exist.

Modes

A number of IO method calls must or may specify a mode for the stream; the mode determines how stream is to be accessible, including:

Whether the stream is to be read-only, write-only, or read-write.
Whether the stream is positioned at its beginning or its end.
Whether the stream treats data as text-only or binary.
The external and internal encodings.

Mode Specified as an Integer

When mode is an integer it must be one or more (combined by bitwise OR (|) of the modes defined in File::Constants:

File::RDONLY: Open for reading only.
File::WRONLY: Open for writing only.
File::RDWR: Open for reading and writing.
File::APPEND: Open for appending only.
File::CREAT: Create file if it does not exist.
File::EXCL: Raise an exception if File::CREAT is given and the file exists.

Examples:

File.new('t.txt', File::RDONLY)
File.new('t.tmp', File::RDWR | File::CREAT | File::EXCL)

Note: Method IO#set_encoding does not allow the mode to be specified as an integer.

Mode Specified As a String

When mode is a string it must begin with one of the following:

'r': Read-only stream, positioned at the beginning; the stream cannot be changed to writable.
'w': Write-only stream, positioned at the beginning; the stream cannot be changed to readable.
'a': Write-only stream, positioned at the end; every write appends to the end; the stream cannot be changed to readable.
'r+': Read-write stream, positioned at the beginning.
'w+': Read-write stream, positioned at the end.
'a+': Read-write stream, positioned at the end.

For a writable file stream (that is, any except read-only), the file is truncated to zero if it exists, and is created if it does not exist.

Examples:

File.open('t.txt', 'r')
File.open('t.tmp', 'w')

Either of the following may be suffixed to any of the above:

't': Text data; sets the default external encoding to Encoding::UTF_8; on Windows, enables conversion between EOL and CRLF.
'b': Binary data; sets the default external encoding to Encoding::ASCII_8BIT; on Windows, suppresses conversion between EOL and CRLF.

If neither is given, the stream defaults to text data.

Examples:

File.open('t.txt', 'rt')
File.open('t.dat', 'rb')

The following may be suffixed to any writable mode above:

'x': Creates the file if it does not exist; raises an exception if the file exists.

Example:

File.open('t.tmp', 'wx')

Finally, the mode string may specify encodings – either external encoding only or both external and internal encodings – by appending one or both encoding names, separated by colons:

f = File.new('t.dat', 'rb')
f.external_encoding # => #<Encoding:ASCII-8BIT>
f.internal_encoding # => nil
f = File.new('t.dat', 'rb:UTF-16')
f.external_encoding # => #<Encoding:UTF-16 (dummy)>
f.internal_encoding # => nil
f = File.new('t.dat', 'rb:UTF-16:UTF-16')
f.external_encoding # => #<Encoding:UTF-16 (dummy)>
f.internal_encoding # => #<Encoding:UTF-16>

The numerous encoding names are available in array Encoding.name_list:

Encoding.name_list.size    # => 175
Encoding.name_list.take(3) # => ["ASCII-8BIT", "UTF-8", "US-ASCII"]

Encodings

When the external encoding is set, strings read are tagged by that encoding when reading, and strings written are converted to that encoding when writing.

When both external and internal encodings are set, strings read are converted from external to internal encoding, and strings written are converted from internal to external encoding. For further details about transcoding input and output, see Encoding.

If the external encoding is 'BOM|UTF-8', 'BOM|UTF-16LE' or 'BOM|UTF16-BE', Ruby checks for a Unicode BOM in the input document to help determine the encoding. For UTF-16 encodings the file open mode must be binary. If the BOM is found, it is stripped and the external encoding from the BOM is used.

Note that the BOM-style encoding option is case insensitive, so ‘bom|utf-8’ is also valid.)

Open Options

A number of IO methods accept an optional parameter opts, which determines how a new stream is to be opened:

:mode: Stream mode.
:flags: Integer file open flags; If mode is also given, the two are bitwise-ORed.
:external_encoding: External encoding for the stream.
:internal_encoding: Internal encoding for the stream. '-' is a synonym for the default internal encoding. If the value is nil no conversion occurs.
:encoding: Specifies external and internal encodings as 'extern:intern'.
:textmode: If a truthy value, specifies the mode as text-only, binary otherwise.
:binmode: If a truthy value, specifies the mode as binary, text-only otherwise.
:autoclose: If a truthy value, specifies that the fd will close when the stream closes; otherwise it remains open.

Also available are the options offered in String#encode, which may control conversion between external internal encoding.

Getline Options

A number of IO methods accept optional keyword arguments that determine how a stream is to be treated:

:chomp: If true, line separators are omitted; default is false.

Position

An IO stream has a position, which is the non-negative integer offset (in bytes) in the stream where the next read or write will occur.

Note that a text stream may have multi-byte characters, so a text stream whose position is n (bytes) may not have n characters preceding the current position – there may be fewer.

A new stream is initially positioned:

At the beginning (position 0) if its mode is 'r', 'w', or 'r+'.
At the end (position self.size) if its mode is 'a', 'w+', or 'a+'.

Methods to query the position:

IO#tell and its alias IO#pos return the position for an open stream.
IO#eof? and its alias IO#eof return whether the position is at the end of a readable stream.

Reading from a stream usually changes its position:

f = File.open('t.txt')
f.tell     # => 0
f.readline # => "This is line one.\n"
f.tell     # => 19
f.readline # => "This is the second line.\n"
f.tell     # => 45
f.eof?     # => false
f.readline # => "Here's the third line.\n"
f.eof?     # => true

Writing to a stream usually changes its position:

f = File.open('t.tmp', 'w')
f.tell         # => 0
f.write('foo') # => 3
f.tell         # => 3
f.write('bar') # => 3
f.tell         # => 6

Iterating over a stream usually changes its position:

f = File.open('t.txt')
f.each do |line|
  p "position=#{f.pos} eof?=#{f.eof?} line=#{line}"
end

Output:

"position=19 eof?=false line=This is line one.\n"
"position=45 eof?=false line=This is the second line.\n"
"position=70 eof?=true line=This is the third line.\n"

The position may also be changed by certain other methods:

IO#pos= and IO#seek change the position to a specified offset.
IO#rewind changes the position to the beginning.

Line Number

A readable IO stream has a line number, which is the non-negative integer line number in the stream where the next read will occur.

A new stream is initially has line number 0.

Method IO#lineno returns the line number.

Reading lines from a stream usually changes its line number:

f = File.open('t.txt', 'r')
f.lineno   # => 0
f.readline # => "This is line one.\n"
f.lineno   # => 1
f.readline # => "This is the second line.\n"
f.lineno   # => 2
f.readline # => "Here's the third line.\n"
f.lineno   # => 3
f.eof?     # => true

Iterating over lines in a stream usually changes its line number:

f = File.open('t.txt')
f.each_line do |line|
  p "position=#{f.pos} eof?=#{f.eof?} line=#{line}"
end

Output:

"position=19 eof?=false line=This is line one.\n"
"position=45 eof?=false line=This is the second line.\n"
"position=70 eof?=true line=This is the third line.\n"

What’s Here

First, what’s elsewhere. Class IO:

Inherits from class Object.
Includes module Enumerable, which provides dozens of additional methods.

Here, class IO provides methods that are useful for:

Creating
Reading
Writing
Positioning
Iterating
Settings
Querying
Buffering
Low-Level Access
Other

Creating

::new (aliased as ::for_fd)

Creates and returns a new IO object for the given integer file descriptor.
::open

Creates a new IO object.
::pipe

Creates a connected pair of reader and writer IO objects.
::popen

Creates an IO object to interact with a subprocess.
::select

Selects which given IO instances are ready for reading,

writing, or have pending exceptions.

Reading

::binread

Returns a binary string with all or a subset of bytes from the given file.
::read

Returns a string with all or a subset of bytes from the given file.
::readlines

Returns an array of strings, which are the lines from the given file.
getbyte

Returns the next 8-bit byte read from self as an integer.
getc

Returns the next character read from self as a string.
gets

Returns the line read from self.
pread

Returns all or the next n bytes read from self, not updating the receiver’s offset.
read

Returns all remaining or the next n bytes read from self for a given n.
read_nonblock

the next n bytes read from self for a given n, in non-block mode.
readbyte

Returns the next byte read from self; same as getbyte, but raises an exception on end-of-file.
readchar

Returns the next character read from self; same as getc, but raises an exception on end-of-file.
readline

Returns the next line read from self; same as getline, but raises an exception of end-of-file.
readlines

Returns an array of all lines read read from self.
readpartial

Returns up to the given number of bytes from self.

Writing

::binwrite

Writes the given string to the file at the given filepath, in binary mode.
::write

Writes the given string to self.
:<<

Appends the given string to self.
print

Prints last read line or given objects to self.
printf

Writes to self based on the given format string and objects.
putc

Writes a character to self.
puts

Writes lines to self, making sure line ends with a newline.
pwrite

Writes the given string at the given offset, not updating the receiver’s offset.
write

Writes one or more given strings to self.
write_nonblock

Writes one or more given strings to self in non-blocking mode.

Positioning

lineno

Returns the current line number in self.
lineno=

Sets the line number is self.
pos (aliased as tell)

Returns the current byte offset in self.
pos=

Sets the byte offset in self.
reopen

Reassociates self with a new or existing IO stream.
rewind

Positions self to the beginning of input.
seek

Sets the offset for self relative to given position.

Iterating

::foreach

Yields each line of given file to the block.
each (aliased as each_line)

Calls the given block with each successive line in self.
each_byte

Calls the given block with each successive byte in self as an integer.
each_char

Calls the given block with each successive character in self as a string.
each_codepoint

Calls the given block with each successive codepoint in self as an integer.

Settings

autoclose=

Sets whether self auto-closes.
binmode

Sets self to binary mode.
close

Closes self.
close_on_exec=

Sets the close-on-exec flag.
close_read

Closes self for reading.
close_write

Closes self for writing.
set_encoding

Sets the encoding for self.
set_encoding_by_bom

Sets the encoding for self, based on its Unicode byte-order-mark.
sync=

Sets the sync-mode to the given value.

Querying

autoclose?

Returns whether self auto-closes.
binmode?

Returns whether self is in binary mode.
close_on_exec?

Returns the close-on-exec flag for self.
closed?

Returns whether self is closed.
eof? (aliased as eof)

Returns whether self is at end-of-file.
external_encoding

Returns the external encoding object for self.
fileno (aliased as to_i)

Returns the integer file descriptor for self
internal_encoding

Returns the internal encoding object for self.
pid

Returns the process ID of a child process associated with self, if self was created by ::popen.
stat

Returns the File::Stat object containing status information for self.
sync

Returns whether self is in sync-mode.
tty (aliased as isatty)

Returns whether self is a terminal.

Buffering

fdatasync

Immediately writes all buffered data in self to disk.
flush

Flushes any buffered data within self to the underlying operating system.
fsync

Immediately writes all buffered data and attributes in self to disk.
ungetbyte

Prepends buffer for self with given integer byte or string.
ungetc

Prepends buffer for self with given string.

Low-Level Access

::sysopen

Opens the file given by its path, returning the integer file descriptor.
advise

Announces the intention to access data from self in a specific way.
fcntl

Passes a low-level command to the file specified by the given file descriptor.
ioctl

Passes a low-level command to the device specified by the given file descriptor.
sysread

Returns up to the next n bytes read from self using a low-level read.
sysseek

Sets the offset for self.
syswrite

Writes the given string to self using a low-level write.

Other

::copy_stream

Copies data from a source to a destination, each of which is a filepath or an IO-like object.
::try_convert

Returns a new IO object resulting from converting the given object.
inspect

Returns the string representation of self.

Constants

READABLE

No documentation available

WRITABLE

No documentation available

PRIORITY

No documentation available

EWOULDBLOCKWaitReadable

same as IO::EAGAINWaitReadable

EWOULDBLOCKWaitWritable

same as IO::EAGAINWaitWritable

SEEK_SET

Set I/O position from the beginning

SEEK_CUR

Set I/O position from the current position

SEEK_END

Set I/O position from the end

SEEK_DATA

Set I/O position to the next location containing data

SEEK_HOLE

Set I/O position to the next hole

Class Methods

IO.binread(name, [length [, offset]]) → string

File.binread(name, [length [, offset]]) → string

io.c View on GitHub

          
            static VALUE
rb_io_s_binread(int argc, VALUE *argv, VALUE io)
{
    VALUE offset;
    struct foreach_arg arg;
    enum {
        fmode = FMODE_READABLE|FMODE_BINMODE,
        oflags = O_RDONLY
#ifdef O_BINARY
                |O_BINARY
#endif
    };
    convconfig_t convconfig = {NULL, NULL, 0, Qnil};

    rb_scan_args(argc, argv, "12", NULL, NULL, &offset);
    FilePathValue(argv[0]);
    convconfig.enc = rb_ascii8bit_encoding();
    arg.io = rb_io_open_generic(io, argv[0], oflags, fmode, &convconfig, 0);
    if (NIL_P(arg.io)) return Qnil;
    arg.argv = argv+1;
    arg.argc = (argc > 1) ? 1 : 0;
    if (!NIL_P(offset)) {
        struct seek_arg sarg;
        int state = 0;
        sarg.io = arg.io;
        sarg.offset = offset;
        sarg.mode = SEEK_SET;
        rb_protect(seek_before_access, (VALUE)&sarg, &state);
        if (state) {
            rb_io_close(arg.io);
            rb_jump_tag(state);
        }
    }
    return rb_ensure(io_s_read, (VALUE)&arg, rb_io_close, arg.io);
}

Opens the file, optionally seeks to the given offset, then returns length bytes (defaulting to the rest of the file). binread ensures the file is closed before returning. The open mode would be "rb:ASCII-8BIT".

If name starts with a pipe character ("|") and the receiver is the IO class, a subprocess is created in the same way as Kernel#open, and its output is returned. Consider to use File.binread to disable the behavior of subprocess invocation.

File.binread("testfile")           #=> "This is line one\nThis is line two\nThis is line three\nAnd so on...\n"
File.binread("testfile", 20)       #=> "This is line one\nThi"
File.binread("testfile", 20, 10)   #=> "ne one\nThis is line "
IO.binread("| cat testfile")       #=> "This is line one\nThis is line two\nThis is line three\nAnd so on...\n"

See also IO.read for details about name and open_args.

IO.binwrite(name, string, [offset]) → integer

IO.binwrite(name, string, [offset], open_args) → integer

File.binwrite(name, string, [offset]) → integer

File.binwrite(name, string, [offset], open_args) → integer

io.c View on GitHub

          
            static VALUE
rb_io_s_binwrite(int argc, VALUE *argv, VALUE io)
{
    return io_s_write(argc, argv, io, 1);
}

Same as IO.write except opening the file in binary mode and ASCII-8BIT encoding ("wb:ASCII-8BIT").

If name starts with a pipe character ("|") and the receiver is the IO class, a subprocess is created in the same way as Kernel#open, and its output is returned. Consider to use File.binwrite to disable the behavior of subprocess invocation.

See also IO.read for details about name and open_args.

IO.console → #<File:/dev/tty>

IO.console(sym, *args)

ext/io/console/console.c View on GitHub

          
            static VALUE
console_dev(int argc, VALUE *argv, VALUE klass)
{
    VALUE con = 0;
    rb_io_t *fptr;
    VALUE sym = 0;

    rb_check_arity(argc, 0, UNLIMITED_ARGUMENTS);
    if (argc) {
        Check_Type(sym = argv[0], T_SYMBOL);
    }
    if (klass == rb_cIO) klass = rb_cFile;
    if (rb_const_defined(klass, id_console)) {
        con = rb_const_get(klass, id_console);
        if (!RB_TYPE_P(con, T_FILE) ||
            (!(fptr = RFILE(con)->fptr) || GetReadFD(fptr) == -1)) {
            rb_const_remove(klass, id_console);
            con = 0;
        }
    }
    if (sym) {
        if (sym == ID2SYM(id_close) && argc == 1) {
            if (con) {
                rb_io_close(con);
                rb_const_remove(klass, id_console);
                con = 0;
            }
            return Qnil;
        }
    }
    if (!con) {
        VALUE args[2];
#if defined HAVE_TERMIOS_H || defined HAVE_TERMIO_H || defined HAVE_SGTTY_H
# define CONSOLE_DEVICE "/dev/tty"
#elif defined _WIN32
# define CONSOLE_DEVICE "con$"
# define CONSOLE_DEVICE_FOR_READING "conin$"
# define CONSOLE_DEVICE_FOR_WRITING "conout$"
#endif
#ifndef CONSOLE_DEVICE_FOR_READING
# define CONSOLE_DEVICE_FOR_READING CONSOLE_DEVICE
#endif
#ifdef CONSOLE_DEVICE_FOR_WRITING
        VALUE out;
        rb_io_t *ofptr;
#endif
        int fd;

#ifdef CONSOLE_DEVICE_FOR_WRITING
        fd = rb_cloexec_open(CONSOLE_DEVICE_FOR_WRITING, O_RDWR, 0);
        if (fd < 0) return Qnil;
        rb_update_max_fd(fd);
        args[1] = INT2FIX(O_WRONLY);
        args[0] = INT2NUM(fd);
        out = rb_class_new_instance(2, args, klass);
#endif
        fd = rb_cloexec_open(CONSOLE_DEVICE_FOR_READING, O_RDWR, 0);
        if (fd < 0) {
#ifdef CONSOLE_DEVICE_FOR_WRITING
            rb_io_close(out);
#endif
            return Qnil;
        }
        rb_update_max_fd(fd);
        args[1] = INT2FIX(O_RDWR);
        args[0] = INT2NUM(fd);
        con = rb_class_new_instance(2, args, klass);
        GetOpenFile(con, fptr);
        fptr->pathv = rb_obj_freeze(rb_str_new2(CONSOLE_DEVICE));
#ifdef CONSOLE_DEVICE_FOR_WRITING
        GetOpenFile(out, ofptr);
        ofptr->pathv = fptr->pathv;
        fptr->tied_io_for_writing = out;
        ofptr->mode |= FMODE_SYNC;
#endif
        fptr->mode |= FMODE_SYNC;
        rb_const_set(klass, id_console, con);
    }
    if (sym) {
        return rb_f_send(argc, argv, con);
    }
    return con;
}

Returns an File instance opened console.

If sym is given, it will be sent to the opened console with args and the result will be returned instead of the console IO itself.

You must require ‘io/console’ to use this method.

console_size

ext/io/console/lib/console/size.rb View on GitHub

An alias for default_console_size

IO.copy_stream(src, dst)

IO.copy_stream(src, dst, copy_length)

IO.copy_stream(src, dst, copy_length, src_offset)

io.c View on GitHub

          
            static VALUE
rb_io_s_copy_stream(int argc, VALUE *argv, VALUE io)
{
    VALUE src, dst, length, src_offset;
    struct copy_stream_struct st;

    MEMZERO(&st, struct copy_stream_struct, 1);

    rb_scan_args(argc, argv, "22", &src, &dst, &length, &src_offset);

    st.src = src;
    st.dst = dst;

    st.src_fptr = NULL;
    st.dst_fptr = NULL;

    if (NIL_P(length))
        st.copy_length = (off_t)-1;
    else
        st.copy_length = NUM2OFFT(length);

    if (NIL_P(src_offset))
        st.src_offset = (off_t)-1;
    else
        st.src_offset = NUM2OFFT(src_offset);

    rb_ensure(copy_stream_body, (VALUE)&st, copy_stream_finalize, (VALUE)&st);

    return OFFT2NUM(st.total);
}

IO.copy_stream copies src to dst. src and dst is either a filename or an IO-like object. IO-like object for src should have readpartial or read method. IO-like object for dst should have write method. (Specialized mechanisms, such as sendfile system call, may be used on appropriate situation.)

This method returns the number of bytes copied.

If optional arguments are not given, the start position of the copy is the beginning of the filename or the current file offset of the IO. The end position of the copy is the end of file.

If copy_length is given, No more than copy_length bytes are copied.

If src_offset is given, it specifies the start position of the copy.

When src_offset is specified and src is an IO, IO.copy_stream doesn’t move the current file offset.

default_console_size

ext/io/console/lib/console/size.rb View on GitHub

          
            # File tmp/rubies/ruby-3.1.3/ext/io/console/lib/console/size.rb, line 3
def IO.default_console_size
  [
    ENV["LINES"].to_i.nonzero? || 25,
    ENV["COLUMNS"].to_i.nonzero? || 80,
  ]
end

fallback to console window size

IO.for_fd(fd, mode [, opt]) → io

io.c View on GitHub

          
            static VALUE
rb_io_s_for_fd(int argc, VALUE *argv, VALUE klass)
{
    VALUE io = rb_obj_alloc(klass);
    rb_io_initialize(argc, argv, io);
    return io;
}

Synonym for IO.new.

IO.foreach(name, sep=$/ [, getline_args, open_args]) {|line| block } → nil

IO.foreach(name, limit [, getline_args, open_args]) {|line| block } → nil

IO.foreach(name, sep, limit [, getline_args, open_args]) {|line| block } → nil

IO.foreach(...) → an_enumerator

File.foreach(name, sep=$/ [, getline_args, open_args]) {|line| block } → nil

File.foreach(name, limit [, getline_args, open_args]) {|line| block } → nil

File.foreach(name, sep, limit [, getline_args, open_args]) {|line| block } → nil

File.foreach(...) → an_enumerator

io.c View on GitHub

          
            static VALUE
rb_io_s_foreach(int argc, VALUE *argv, VALUE self)
{
    VALUE opt;
    int orig_argc = argc;
    struct foreach_arg arg;
    struct getline_arg garg;

    argc = rb_scan_args(argc, argv, "13:", NULL, NULL, NULL, NULL, &opt);
    RETURN_ENUMERATOR(self, orig_argc, argv);
    extract_getline_args(argc-1, argv+1, &garg);
    open_key_args(self, argc, argv, opt, &arg);
    if (NIL_P(arg.io)) return Qnil;
    extract_getline_opts(opt, &garg);
    check_getline_args(&garg.rs, &garg.limit, garg.io = arg.io);
    return rb_ensure(io_s_foreach, (VALUE)&garg, rb_io_close, arg.io);
}

Executes the block for every line in the named I/O port, where lines are separated by sep.

If no block is given, an enumerator is returned instead.

If name starts with a pipe character ("|") and the receiver is the IO class, a subprocess is created in the same way as Kernel#open, and its output is returned. Consider to use File.foreach to disable the behavior of subprocess invocation.

File.foreach("testfile") {|x| print "GOT ", x }
IO.foreach("| cat testfile") {|x| print "GOT ", x }

produces:

GOT This is line one
GOT This is line two
GOT This is line three
GOT And so on...

If the last argument is a hash, it’s the keyword argument to open. See IO.readlines for details about getline_args. And see also IO.read for details about open_args.

IO.new(fd [, mode] [, opt]) → io

io.c View on GitHub

          
            static VALUE
rb_io_initialize(int argc, VALUE *argv, VALUE io)
{
    VALUE fnum, vmode;
    rb_io_t *fp;
    int fd, fmode, oflags = O_RDONLY;
    convconfig_t convconfig;
    VALUE opt;
#if defined(HAVE_FCNTL) && defined(F_GETFL)
    int ofmode;
#else
    struct stat st;
#endif


    argc = rb_scan_args(argc, argv, "11:", &fnum, &vmode, &opt);
    rb_io_extract_modeenc(&vmode, 0, opt, &oflags, &fmode, &convconfig);

    fd = NUM2INT(fnum);
    if (rb_reserved_fd_p(fd)) {
        rb_raise(rb_eArgError, "The given fd is not accessible because RubyVM reserves it");
    }
#if defined(HAVE_FCNTL) && defined(F_GETFL)
    oflags = fcntl(fd, F_GETFL);
    if (oflags == -1) rb_sys_fail(0);
#else
    if (fstat(fd, &st) < 0) rb_sys_fail(0);
#endif
    rb_update_max_fd(fd);
#if defined(HAVE_FCNTL) && defined(F_GETFL)
    ofmode = rb_io_oflags_fmode(oflags);
    if (NIL_P(vmode)) {
        fmode = ofmode;
    }
    else if ((~ofmode & fmode) & FMODE_READWRITE) {
        VALUE error = INT2FIX(EINVAL);
        rb_exc_raise(rb_class_new_instance(1, &error, rb_eSystemCallError));
    }
#endif
    if (!NIL_P(opt) && rb_hash_aref(opt, sym_autoclose) == Qfalse) {
        fmode |= FMODE_PREP;
    }
    MakeOpenFile(io, fp);
    fp->self = io;
    fp->fd = fd;
    fp->mode = fmode;
    fp->encs = convconfig;
    clear_codeconv(fp);
    io_check_tty(fp);
    if (fileno(stdin) == fd)
        fp->stdio_file = stdin;
    else if (fileno(stdout) == fd)
        fp->stdio_file = stdout;
    else if (fileno(stderr) == fd)
        fp->stdio_file = stderr;

    if (fmode & FMODE_SETENC_BY_BOM) io_set_encoding_by_bom(io);
    return io;
}

Returns a new IO object (a stream) for the given integer file descriptor fd and mode string. opt may be used to specify parts of mode in a more readable fashion. See also IO.sysopen and IO.for_fd.

IO.new is called by various File and IO opening methods such as IO::open, Kernel#open, and File::open.

Open Mode

When mode is an integer it must be combination of the modes defined in File::Constants (File::RDONLY, File::WRONLY|File::CREAT). See the open(2) man page for more information.

When mode is a string it must be in one of the following forms:

fmode
fmode ":" ext_enc
fmode ":" ext_enc ":" int_enc
fmode ":" "BOM|UTF-*"

fmode is an IO open mode string, ext_enc is the external encoding for the IO and int_enc is the internal encoding.

`IO` Open Mode

Ruby allows the following open modes:

"r"  Read-only, starts at beginning of file  (default mode).

"r+" Read-write, starts at beginning of file.

"w"  Write-only, truncates existing file
     to zero length or creates a new file for writing.

"w+" Read-write, truncates existing file to zero length
     or creates a new file for reading and writing.

"a"  Write-only, each write call appends data at end of file.
     Creates a new file for writing if file does not exist.

"a+" Read-write, each write call appends data at end of file.
     Creates a new file for reading and writing if file does
     not exist.

The following modes must be used separately, and along with one or more of the modes seen above.

"b"  Binary file mode
     Suppresses EOL <-> CRLF conversion on Windows. And
     sets external encoding to ASCII-8BIT unless explicitly
     specified.

"t"  Text file mode

The exclusive access mode (“x”) can be used together with “w” to ensure the file is created. Errno::EEXIST is raised when it already exists. It may not be supported with all kinds of streams (e.g. pipes).

When the open mode of original IO is read only, the mode cannot be changed to be writable. Similarly, the open mode cannot be changed from write only to readable.

When such a change is attempted the error is raised in different locations according to the platform.

`IO` `Encoding`

When ext_enc is specified, strings read will be tagged by the encoding when reading, and strings output will be converted to the specified encoding when writing.

When ext_enc and int_enc are specified read strings will be converted from ext_enc to int_enc upon input, and written strings will be converted from int_enc to ext_enc upon output. See Encoding for further details of transcoding on input and output.

If “BOM|UTF-8”, “BOM|UTF-16LE” or “BOM|UTF16-BE” are used, Ruby checks for a Unicode BOM in the input document to help determine the encoding. For UTF-16 encodings the file open mode must be binary. When present, the BOM is stripped and the external encoding from the BOM is used. When the BOM is missing the given Unicode encoding is used as ext_enc. (The BOM-set encoding option is case insensitive, so “bom|utf-8” is also valid.)

Options

opt can be used instead of mode for improved readability. The following keys are supported:

:mode

Same as mode parameter

:flags

Specifies file open flags as integer. If mode parameter is given, this parameter will be bitwise-ORed.

:external_encoding

External encoding for the IO.

:internal_encoding

Internal encoding for the IO. “-” is a synonym for the default internal encoding.

If the value is nil no conversion occurs.

:encoding

Specifies external and internal encodings as “extern:intern”.

:textmode

If the value is truth value, same as “t” in argument mode.

:binmode

If the value is truth value, same as “b” in argument mode.

:autoclose

If the value is false, the fd will be kept open after this IO instance gets finalized.

Also, opt can have same keys in String#encode for controlling conversion between the external encoding and the internal encoding.

Example 1

fd = IO.sysopen("/dev/tty", "w")
a = IO.new(fd,"w")
$stderr.puts "Hello"
a.puts "World"

Produces:

Hello
World

Example 2

require 'fcntl'

fd = STDERR.fcntl(Fcntl::F_DUPFD)
io = IO.new(fd, mode: 'w:UTF-16LE', cr_newline: true)
io.puts "Hello, World!"

fd = STDERR.fcntl(Fcntl::F_DUPFD)
io = IO.new(fd, mode: 'w', cr_newline: true,
            external_encoding: Encoding::UTF_16LE)
io.puts "Hello, World!"

Both of above print “Hello, World!” in UTF-16LE to standard error output with converting EOL generated by puts to CR.

IO.open(fd, mode="r" [, opt]) → io

IO.open(fd, mode="r" [, opt]) {|io| block } → obj

io.c View on GitHub

          
            static VALUE
rb_io_s_open(int argc, VALUE *argv, VALUE klass)
{
    VALUE io = rb_class_new_instance_kw(argc, argv, klass, RB_PASS_CALLED_KEYWORDS);

    if (rb_block_given_p()) {
        return rb_ensure(rb_yield, io, io_close, io);
    }

    return io;
}

With no associated block, IO.open is a synonym for IO.new. If the optional code block is given, it will be passed io as an argument, and the IO object will automatically be closed when the block terminates. In this instance, IO.open returns the value of the block.

See IO.new for a description of the fd, mode and opt parameters.

IO.pipe → [read_io, write_io]

IO.pipe(ext_enc) → [read_io, write_io]

IO.pipe("ext_enc:int_enc" [, opt]) → [read_io, write_io]

IO.pipe(ext_enc, int_enc [, opt]) → [read_io, write_io]

IO.pipe(...) {|read_io, write_io| ... }

io.c View on GitHub

          
            static VALUE
rb_io_s_pipe(int argc, VALUE *argv, VALUE klass)
{
    int pipes[2], state;
    VALUE r, w, args[3], v1, v2;
    VALUE opt;
    rb_io_t *fptr, *fptr2;
    struct io_encoding_set_args ies_args;
    int fmode = 0;
    VALUE ret;

    argc = rb_scan_args(argc, argv, "02:", &v1, &v2, &opt);
    if (rb_pipe(pipes) < 0)
        rb_sys_fail(0);

    args[0] = klass;
    args[1] = INT2NUM(pipes[0]);
    args[2] = INT2FIX(O_RDONLY);
    r = rb_protect(io_new_instance, (VALUE)args, &state);
    if (state) {
        close(pipes[0]);
        close(pipes[1]);
        rb_jump_tag(state);
    }
    GetOpenFile(r, fptr);

    ies_args.fptr = fptr;
    ies_args.v1 = v1;
    ies_args.v2 = v2;
    ies_args.opt = opt;
    rb_protect(io_encoding_set_v, (VALUE)&ies_args, &state);
    if (state) {
        close(pipes[1]);
        io_close(r);
        rb_jump_tag(state);
    }

    args[1] = INT2NUM(pipes[1]);
    args[2] = INT2FIX(O_WRONLY);
    w = rb_protect(io_new_instance, (VALUE)args, &state);
    if (state) {
        close(pipes[1]);
        if (!NIL_P(r)) rb_io_close(r);
        rb_jump_tag(state);
    }
    GetOpenFile(w, fptr2);
    rb_io_synchronized(fptr2);

    extract_binmode(opt, &fmode);

    if ((fmode & FMODE_BINMODE) && NIL_P(v1)) {
        rb_io_ascii8bit_binmode(r);
        rb_io_ascii8bit_binmode(w);
    }

#if DEFAULT_TEXTMODE
    if ((fptr->mode & FMODE_TEXTMODE) && (fmode & FMODE_BINMODE)) {
        fptr->mode &= ~FMODE_TEXTMODE;
        setmode(fptr->fd, O_BINARY);
    }
#if RUBY_CRLF_ENVIRONMENT
    if (fptr->encs.ecflags & ECONV_DEFAULT_NEWLINE_DECORATOR) {
        fptr->encs.ecflags |= ECONV_UNIVERSAL_NEWLINE_DECORATOR;
    }
#endif
#endif
    fptr->mode |= fmode;
#if DEFAULT_TEXTMODE
    if ((fptr2->mode & FMODE_TEXTMODE) && (fmode & FMODE_BINMODE)) {
        fptr2->mode &= ~FMODE_TEXTMODE;
        setmode(fptr2->fd, O_BINARY);
    }
#endif
    fptr2->mode |= fmode;

    ret = rb_assoc_new(r, w);
    if (rb_block_given_p()) {
        VALUE rw[2];
        rw[0] = r;
        rw[1] = w;
        return rb_ensure(rb_yield, ret, pipe_pair_close, (VALUE)rw);
    }
    return ret;
}

Creates a pair of pipe endpoints (connected to each other) and returns them as a two-element array of IO objects: [ read_io, write_io ].

If a block is given, the block is called and returns the value of the block. read_io and write_io are sent to the block as arguments. If read_io and write_io are not closed when the block exits, they are closed. i.e. closing read_io and/or write_io doesn’t cause an error.

Not available on all platforms.

If an encoding (encoding name or encoding object) is specified as an optional argument, read string from pipe is tagged with the encoding specified. If the argument is a colon separated two encoding names “A:B”, the read string is converted from encoding A (external encoding) to encoding B (internal encoding), then tagged with B. If two optional arguments are specified, those must be encoding objects or encoding names, and the first one is the external encoding, and the second one is the internal encoding. If the external encoding and the internal encoding is specified, optional hash argument specify the conversion option.

In the example below, the two processes close the ends of the pipe that they are not using. This is not just a cosmetic nicety. The read end of a pipe will not generate an end of file condition if there are any writers with the pipe still open. In the case of the parent process, the rd.read will never return if it does not first issue a wr.close.

rd, wr = IO.pipe

if fork
  wr.close
  puts "Parent got: <#{rd.read}>"
  rd.close
  Process.wait
else
  rd.close
  puts "Sending message to parent"
  wr.write "Hi Dad"
  wr.close
end

produces:

Sending message to parent
Parent got: <Hi Dad>

IO.popen([env,] cmd, mode="r" [, opt]) → io

IO.popen([env,] cmd, mode="r" [, opt]) {|io| block } → obj

io.c View on GitHub

          
            static VALUE
rb_io_s_popen(int argc, VALUE *argv, VALUE klass)
{
    VALUE pname, pmode = Qnil, opt = Qnil, env = Qnil;

    if (argc > 1 && !NIL_P(opt = rb_check_hash_type(argv[argc-1]))) --argc;
    if (argc > 1 && !NIL_P(env = rb_check_hash_type(argv[0]))) --argc, ++argv;
    switch (argc) {
      case 2:
        pmode = argv[1];
      case 1:
        pname = argv[0];
        break;
      default:
        {
            int ex = !NIL_P(opt);
            rb_error_arity(argc + ex, 1 + ex, 2 + ex);
        }
    }
    return popen_finish(rb_io_popen(pname, pmode, env, opt), klass);
}

Runs the specified command as a subprocess; the subprocess’s standard input and output will be connected to the returned IO object.

The PID of the started process can be obtained by IO#pid method.

cmd is a string or an array as follows.

cmd:
  "-"                                      : fork
  commandline                              : command line string which is passed to a shell
  [env, cmdname, arg1, ..., opts]          : command name and zero or more arguments (no shell)
  [env, [cmdname, argv0], arg1, ..., opts] : command name, argv[0] and zero or more arguments (no shell)
(env and opts are optional.)

If cmd is a String “-”, then a new instance of Ruby is started as the subprocess.

If cmd is an Array of String, then it will be used as the subprocess’s argv bypassing a shell. The array can contain a hash at first for environments and a hash at last for options similar to spawn.

The default mode for the new file object is “r”, but mode may be set to any of the modes listed in the description for class IO. The last argument opt qualifies mode.

# set IO encoding
IO.popen("nkf -e filename", :external_encoding=>"EUC-JP") {|nkf_io|
  euc_jp_string = nkf_io.read
}

# merge standard output and standard error using
# spawn option.  See the document of Kernel.spawn.
IO.popen(["ls", "/", :err=>[:child, :out]]) {|ls_io|
  ls_result_with_error = ls_io.read
}

# spawn options can be mixed with IO options
IO.popen(["ls", "/"], :err=>[:child, :out]) {|ls_io|
  ls_result_with_error = ls_io.read
}

Raises exceptions which IO.pipe and Kernel.spawn raise.

If a block is given, Ruby will run the command as a child connected to Ruby with a pipe. Ruby’s end of the pipe will be passed as a parameter to the block. At the end of block, Ruby closes the pipe and sets $?. In this case IO.popen returns the value of the block.

If a block is given with a cmd of “-”, the block will be run in two separate processes: once in the parent, and once in a child. The parent process will be passed the pipe object as a parameter to the block, the child version of the block will be passed nil, and the child’s standard in and standard out will be connected to the parent through the pipe. Not available on all platforms.

f = IO.popen("uname")
p f.readlines
f.close
puts "Parent is #{Process.pid}"
IO.popen("date") {|f| puts f.gets }
IO.popen("-") {|f| $stderr.puts "#{Process.pid} is here, f is #{f.inspect}"}
p $?
IO.popen(%w"sed -e s|^|<foo>| -e s&$&;zot;&", "r+") {|f|
  f.puts "bar"; f.close_write; puts f.gets
}

produces:

["Linux\n"]
Parent is 21346
Thu Jan 15 22:41:19 JST 2009
21346 is here, f is #<IO:fd 3>
21352 is here, f is nil
#<Process::Status: pid 21352 exit 0>
<foo>bar;zot;

IO.read(name, [length [, offset]] [, opt]) → string

File.read(name, [length [, offset]] [, opt]) → string

io.c View on GitHub

          
            static VALUE
rb_io_s_read(int argc, VALUE *argv, VALUE io)
{
    VALUE opt, offset;
    struct foreach_arg arg;

    argc = rb_scan_args(argc, argv, "13:", NULL, NULL, &offset, NULL, &opt);
    open_key_args(io, argc, argv, opt, &arg);
    if (NIL_P(arg.io)) return Qnil;
    if (!NIL_P(offset)) {
        struct seek_arg sarg;
        int state = 0;
        sarg.io = arg.io;
        sarg.offset = offset;
        sarg.mode = SEEK_SET;
        rb_protect(seek_before_access, (VALUE)&sarg, &state);
        if (state) {
            rb_io_close(arg.io);
            rb_jump_tag(state);
        }
        if (arg.argc == 2) arg.argc = 1;
    }
    return rb_ensure(io_s_read, (VALUE)&arg, rb_io_close, arg.io);
}

Opens the file, optionally seeks to the given offset, then returns length bytes (defaulting to the rest of the file). read ensures the file is closed before returning.

If name starts with a pipe character ("|") and the receiver is the IO class, a subprocess is created in the same way as Kernel#open, and its output is returned. Consider to use File.read to disable the behavior of subprocess invocation.

Options

The options hash accepts the following keys:

:encoding

string or encoding

Specifies the encoding of the read string. :encoding will be ignored if length is specified. See Encoding.aliases for possible encodings.

:mode

string or integer

Specifies the mode argument for open(). It must start with an “r”, otherwise it will cause an error. See IO.new for the list of possible modes.

:open_args

array

Specifies arguments for open() as an array. This key can not be used in combination with either :encoding or :mode.

Examples:

File.read("testfile")            #=> "This is line one\nThis is line two\nThis is line three\nAnd so on...\n"
File.read("testfile", 20)        #=> "This is line one\nThi"
File.read("testfile", 20, 10)    #=> "ne one\nThis is line "
File.read("binfile", mode: "rb") #=> "\xF7\x00\x00\x0E\x12"
IO.read("|ls -a")                #=> ".\n..\n"...

IO.readlines(name, sep=$/ [, getline_args, open_args]) → array

IO.readlines(name, limit [, getline_args, open_args]) → array

IO.readlines(name, sep, limit [, getline_args, open_args]) → array

File.readlines(name, sep=$/ [, getline_args, open_args]) → array

File.readlines(name, limit [, getline_args, open_args]) → array

File.readlines(name, sep, limit [, getline_args, open_args]) → array

io.c View on GitHub

          
            static VALUE
rb_io_s_readlines(int argc, VALUE *argv, VALUE io)
{
    VALUE opt;
    struct foreach_arg arg;
    struct getline_arg garg;

    argc = rb_scan_args(argc, argv, "13:", NULL, NULL, NULL, NULL, &opt);
    extract_getline_args(argc-1, argv+1, &garg);
    open_key_args(io, argc, argv, opt, &arg);
    if (NIL_P(arg.io)) return Qnil;
    extract_getline_opts(opt, &garg);
    check_getline_args(&garg.rs, &garg.limit, garg.io = arg.io);
    return rb_ensure(io_s_readlines, (VALUE)&garg, rb_io_close, arg.io);
}

Reads the entire file specified by name as individual lines, and returns those lines in an array. Lines are separated by sep.

If name starts with a pipe character ("|") and the receiver is the IO class, a subprocess is created in the same way as Kernel#open, and its output is returned. Consider to use File.readlines to disable the behavior of subprocess invocation.

a = File.readlines("testfile")
a[0]   #=> "This is line one\n"

b = File.readlines("testfile", chomp: true)
b[0]   #=> "This is line one"

IO.readlines("|ls -a")     #=> [".\n", "..\n", ...]

If the last argument is a hash, it’s the keyword argument to open.

Options for getline

The options hash accepts the following keys:

:chomp: When the optional chomp keyword argument has a true value, \n, \r, and \r\n will be removed from the end of each line.

See also IO.read for details about name and open_args.

IO.select(read_array [, write_array [, error_array [, timeout]]]) → array or nil

io.c View on GitHub

          
            static VALUE
rb_f_select(int argc, VALUE *argv, VALUE obj)
{
    VALUE timeout;
    struct select_args args;
    struct timeval timerec;
    int i;

    rb_scan_args(argc, argv, "13", &args.read, &args.write, &args.except, &timeout);
    if (NIL_P(timeout)) {
        args.timeout = 0;
    }
    else {
        timerec = rb_time_interval(timeout);
        args.timeout = &timerec;
    }

    for (i = 0; i < numberof(args.fdsets); ++i)
        rb_fd_init(&args.fdsets[i]);

    return rb_ensure(select_call, (VALUE)&args, select_end, (VALUE)&args);
}

Calls select(2) system call. It monitors given arrays of IO objects, waits until one or more of IO objects are ready for reading, are ready for writing, and have pending exceptions respectively, and returns an array that contains arrays of those IO objects. It will return nil if optional timeout value is given and no IO object is ready in timeout seconds.

IO.select peeks the buffer of IO objects for testing readability. If the IO buffer is not empty, IO.select immediately notifies readability. This “peek” only happens for IO objects. It does not happen for IO-like objects such as OpenSSL::SSL::SSLSocket.

The best way to use IO.select is invoking it after nonblocking methods such as read_nonblock, write_nonblock, etc. The methods raise an exception which is extended by IO::WaitReadable or IO::WaitWritable. The modules notify how the caller should wait with IO.select. If IO::WaitReadable is raised, the caller should wait for reading. If IO::WaitWritable is raised, the caller should wait for writing.

So, blocking read (readpartial) can be emulated using read_nonblock and IO.select as follows:

begin
  result = io_like.read_nonblock(maxlen)
rescue IO::WaitReadable
  IO.select([io_like])
  retry
rescue IO::WaitWritable
  IO.select(nil, [io_like])
  retry
end

Especially, the combination of nonblocking methods and IO.select is preferred for IO like objects such as OpenSSL::SSL::SSLSocket. It has to_io method to return underlying IO object. IO.select calls to_io to obtain the file descriptor to wait.

This means that readability notified by IO.select doesn’t mean readability from OpenSSL::SSL::SSLSocket object.

The most likely situation is that OpenSSL::SSL::SSLSocket buffers some data. IO.select doesn’t see the buffer. So IO.select can block when OpenSSL::SSL::SSLSocket#readpartial doesn’t block.

However, several more complicated situations exist.

SSL is a protocol which is sequence of records. The record consists of multiple bytes. So, the remote side of SSL sends a partial record, IO.select notifies readability but OpenSSL::SSL::SSLSocket cannot decrypt a byte and OpenSSL::SSL::SSLSocket#readpartial will block.

Also, the remote side can request SSL renegotiation which forces the local SSL engine to write some data. This means OpenSSL::SSL::SSLSocket#readpartial may invoke write system call and it can block. In such a situation, OpenSSL::SSL::SSLSocket#read_nonblock raises IO::WaitWritable instead of blocking. So, the caller should wait for ready for writability as above example.

The combination of nonblocking methods and IO.select is also useful for streams such as tty, pipe socket socket when multiple processes read from a stream.

Finally, Linux kernel developers don’t guarantee that readability of select(2) means readability of following read(2) even for a single process. See select(2) manual on GNU/Linux system.

Invoking IO.select before IO#readpartial works well as usual. However it is not the best way to use IO.select.

The writability notified by select(2) doesn’t show how many bytes are writable. IO#write method blocks until given whole string is written. So, IO#write(two or more bytes) can block after writability is notified by IO.select. IO#write_nonblock is required to avoid the blocking.

Blocking write (write) can be emulated using write_nonblock and IO.select as follows: IO::WaitReadable should also be rescued for SSL renegotiation in OpenSSL::SSL::SSLSocket.

while 0 < string.bytesize
  begin
    written = io_like.write_nonblock(string)
  rescue IO::WaitReadable
    IO.select([io_like])
    retry
  rescue IO::WaitWritable
    IO.select(nil, [io_like])
    retry
  end
  string = string.byteslice(written..-1)
end

Parameters

read_array: an array of IO objects that wait until ready for read
write_array: an array of IO objects that wait until ready for write
error_array: an array of IO objects that wait for exceptions
timeout: a numeric value in second

Example

rp, wp = IO.pipe
mesg = "ping "
100.times {
  # IO.select follows IO#read.  Not the best way to use IO.select.
  rs, ws, = IO.select([rp], [wp])
  if r = rs[0]
    ret = r.read(5)
    print ret
    case ret
    when /ping/
      mesg = "pong\n"
    when /pong/
      mesg = "ping "
    end
  end
  if w = ws[0]
    w.write(mesg)
  end
}

produces:

ping pong
ping pong
ping pong
(snipped)
ping

IO.sysopen(path, [mode, [perm]]) → integer

io.c View on GitHub

          
            static VALUE
rb_io_s_sysopen(int argc, VALUE *argv, VALUE _)
{
    VALUE fname, vmode, vperm;
    VALUE intmode;
    int oflags, fd;
    mode_t perm;

    rb_scan_args(argc, argv, "12", &fname, &vmode, &vperm);
    FilePathValue(fname);

    if (NIL_P(vmode))
        oflags = O_RDONLY;
    else if (!NIL_P(intmode = rb_check_to_integer(vmode, "to_int")))
        oflags = NUM2INT(intmode);
    else {
        SafeStringValue(vmode);
        oflags = rb_io_modestr_oflags(StringValueCStr(vmode));
    }
    if (NIL_P(vperm)) perm = 0666;
    else              perm = NUM2MODET(vperm);

    RB_GC_GUARD(fname) = rb_str_new4(fname);
    fd = rb_sysopen(fname, oflags, perm);
    return INT2NUM(fd);
}

Opens the given path, returning the underlying file descriptor as a Integer.

IO.sysopen("testfile")   #=> 3

IO.try_convert(object) → new_io or nil

io.c View on GitHub

          
            static VALUE
rb_io_s_try_convert(VALUE dummy, VALUE io)
{
    return rb_io_check_io(io);
}

Attempts to convert object into an IO object via method to_io; returns the new IO object if successful, or nil otherwise:

IO.try_convert(STDOUT)   # => #<IO:<STDOUT>>
IO.try_convert(ARGF)     # => #<IO:<STDIN>>
IO.try_convert('STDOUT') # => nil

IO.write(name, string [, offset]) → integer

IO.write(name, string [, offset] [, opt]) → integer

File.write(name, string [, offset]) → integer

File.write(name, string [, offset] [, opt]) → integer

io.c View on GitHub

          
            static VALUE
rb_io_s_write(int argc, VALUE *argv, VALUE io)
{
    return io_s_write(argc, argv, io, 0);
}

Opens the file, optionally seeks to the given offset, writes string, then returns the length written. write ensures the file is closed before returning. If offset is not given in write mode, the file is truncated. Otherwise, it is not truncated.

If name starts with a pipe character ("|") and the receiver is the IO class, a subprocess is created in the same way as Kernel#open, and its output is returned. Consider to use File.write to disable the behavior of subprocess invocation.

File.write("testfile", "0123456789", 20)  #=> 10
# File could contain:  "This is line one\nThi0123456789two\nThis is line three\nAnd so on...\n"
File.write("testfile", "0123456789")      #=> 10
# File would now read: "0123456789"
IO.write("|tr a-z A-Z", "abc")            #=> 3
# Prints "ABC" to the standard output

If the last argument is a hash, it specifies options for the internal open(). It accepts the following keys:

:encoding

string or encoding

Specifies the encoding of the read string. See Encoding.aliases for possible encodings.

:mode

string or integer

Specifies the mode argument for open(). It must start with “w”, “a”, or “r+”, otherwise it will cause an error. See IO.new for the list of possible modes.

:perm

integer

Specifies the perm argument for open().

:open_args

array

Specifies arguments for open() as an array. This key can not be used in combination with other keys.

See also IO.read for details about name and open_args.

Instance Methods

self << object → self

io.c View on GitHub

          
            VALUE
rb_io_addstr(VALUE io, VALUE str)
{
    rb_io_write(io, str);
    return io;
}

Writes the given object to self, which must be opened for writing (see Modes); returns self; if object is not a string, it is converted via method to_s:

$stdout << 'Hello' << ', ' << 'World!' << "\n"
$stdout << 'foo' << :bar << 2 << "\n"

Output:

Hello, World!
foobar2

ios.advise(advice, offset=0, len=0) → nil

io.c View on GitHub

          
            static VALUE
rb_io_advise(int argc, VALUE *argv, VALUE io)
{
    VALUE advice, offset, len;
    off_t off, l;
    rb_io_t *fptr;

    rb_scan_args(argc, argv, "12", &advice, &offset, &len);
    advice_arg_check(advice);

    io = GetWriteIO(io);
    GetOpenFile(io, fptr);

    off = NIL_P(offset) ? 0 : NUM2OFFT(offset);
    l   = NIL_P(len)    ? 0 : NUM2OFFT(len);

#ifdef HAVE_POSIX_FADVISE
    return do_io_advise(fptr, advice, off, l);
#else
    ((void)off, (void)l);       /* Ignore all hint */
    return Qnil;
#endif
}

Announce an intention to access data from the current file in a specific pattern. On platforms that do not support the posix_fadvise(2) system call, this method is a no-op.

advice is one of the following symbols:

:normal: No advice to give; the default assumption for an open file.
:sequential: The data will be accessed sequentially with lower offsets read before higher ones.
:random: The data will be accessed in random order.
:willneed: The data will be accessed in the near future.
:dontneed: The data will not be accessed in the near future.
:noreuse: The data will only be accessed once.

The semantics of a piece of advice are platform-dependent. See man 2 posix_fadvise for details.

“data” means the region of the current file that begins at offset and extends for len bytes. If len is 0, the region ends at the last byte of the file. By default, both offset and len are 0, meaning that the advice applies to the entire file.

If an error occurs, one of the following exceptions will be raised:

IOError: The IO stream is closed.
Errno::EBADF: The file descriptor of the current file is invalid.
Errno::EINVAL: An invalid value for advice was given.
Errno::ESPIPE: The file descriptor of the current file refers to a FIFO or pipe. (Linux raises Errno::EINVAL in this case).
TypeError: Either advice was not a Symbol, or one of the other arguments was not an Integer.
RangeError: One of the arguments given was too big/small.
This list is not exhaustive; other Errno: exceptions are also possible.

io.autoclose = bool → true or false

io.c View on GitHub

          
            static VALUE
rb_io_set_autoclose(VALUE io, VALUE autoclose)
{
    rb_io_t *fptr;
    GetOpenFile(io, fptr);
    if (!RTEST(autoclose))
        fptr->mode |= FMODE_PREP;
    else
        fptr->mode &= ~FMODE_PREP;
    return autoclose;
}

Sets auto-close flag.

f = open("/dev/null")
IO.for_fd(f.fileno)
# ...
f.gets # may cause Errno::EBADF

f = open("/dev/null")
IO.for_fd(f.fileno).autoclose = false
# ...
f.gets # won't cause Errno::EBADF

ios.autoclose? → true or false

io.c View on GitHub

          
            static VALUE
rb_io_autoclose_p(VALUE io)
{
    rb_io_t *fptr = RFILE(io)->fptr;
    rb_io_check_closed(fptr);
    return (fptr->mode & FMODE_PREP) ? Qfalse : Qtrue;
}

Returns true if the underlying file descriptor of ios will be closed automatically at its finalization, otherwise false.

beep

ext/io/console/console.c View on GitHub

          
            static VALUE
console_beep(VALUE io)
{
    rb_io_t *fptr;
    int fd;

    GetOpenFile(io, fptr);
    fd = GetWriteFD(fptr);
#ifdef _WIN32
    (void)fd;
    MessageBeep(0);
#else
    if (write(fd, "\a", 1) < 0)
        sys_fail_fptr(fptr);
#endif
    return io;
}

No documentation available

ios.binmode → ios

io.c View on GitHub

          
            static VALUE
rb_io_binmode_m(VALUE io)
{
    VALUE write_io;

    rb_io_ascii8bit_binmode(io);

    write_io = GetWriteIO(io);
    if (write_io != io)
        rb_io_ascii8bit_binmode(write_io);
    return io;
}

Puts ios into binary mode. Once a stream is in binary mode, it cannot be reset to nonbinary mode.

newline conversion disabled
encoding conversion disabled
content is treated as ASCII-8BIT

ios.binmode? → true or false

io.c View on GitHub

          
            static VALUE
rb_io_binmode_p(VALUE io)
{
    rb_io_t *fptr;
    GetOpenFile(io, fptr);
    return RBOOL(fptr->mode & FMODE_BINMODE);
}

Returns true if ios is binmode.

check_winsize_changed

ext/io/console/console.c View on GitHub

          
            _WIN32
static VALUE
console_check_winsize_changed(VALUE io)
{
    rb_io_t *fptr;
    HANDLE h;
    DWORD num;

    GetOpenFile(io, fptr);
    h = (HANDLE)rb_w32_get_osfhandle(GetReadFD(fptr));
    while (GetNumberOfConsoleInputEvents(h, &num) && num > 0) {
        INPUT_RECORD rec;
        if (ReadConsoleInput(h, &rec, 1, &num)) {
            if (rec.EventType == WINDOW_BUFFER_SIZE_EVENT) {
                rb_yield(Qnil);
            }
        }
    }
    return io;
}

No documentation available

clear_screen

ext/io/console/console.c View on GitHub

          
            static VALUE
console_clear_screen(VALUE io)
{
    console_erase_screen(io, INT2FIX(2));
    console_goto(io, INT2FIX(0), INT2FIX(0));
    return io;
}

No documentation available

ios.close → nil

io.c View on GitHub

          
            static VALUE
rb_io_close_m(VALUE io)
{
    rb_io_t *fptr = rb_io_get_fptr(io);
    if (fptr->fd < 0) {
        return Qnil;
    }
    rb_io_close(io);
    return Qnil;
}

Closes ios and flushes any pending writes to the operating system. The stream is unavailable for any further data operations; an IOError is raised if such an attempt is made. I/O streams are automatically closed when they are claimed by the garbage collector.

If ios is opened by IO.popen, close sets $?.

Calling this method on closed IO object is just ignored since Ruby 2.3.

ios.close_on_exec = bool → true or false

io.c View on GitHub

          
            static VALUE
rb_io_set_close_on_exec(VALUE io, VALUE arg)
{
    int flag = RTEST(arg) ? FD_CLOEXEC : 0;
    rb_io_t *fptr;
    VALUE write_io;
    int fd, ret;

    write_io = GetWriteIO(io);
    if (io != write_io) {
        GetOpenFile(write_io, fptr);
        if (fptr && 0 <= (fd = fptr->fd)) {
            if ((ret = fcntl(fptr->fd, F_GETFD)) == -1) rb_sys_fail_path(fptr->pathv);
            if ((ret & FD_CLOEXEC) != flag) {
                ret = (ret & ~FD_CLOEXEC) | flag;
                ret = fcntl(fd, F_SETFD, ret);
                if (ret != 0) rb_sys_fail_path(fptr->pathv);
            }
        }

    }

    GetOpenFile(io, fptr);
    if (fptr && 0 <= (fd = fptr->fd)) {
        if ((ret = fcntl(fd, F_GETFD)) == -1) rb_sys_fail_path(fptr->pathv);
        if ((ret & FD_CLOEXEC) != flag) {
            ret = (ret & ~FD_CLOEXEC) | flag;
            ret = fcntl(fd, F_SETFD, ret);
            if (ret != 0) rb_sys_fail_path(fptr->pathv);
        }
    }
    return Qnil;
}

Sets a close-on-exec flag.

f = open("/dev/null")
f.close_on_exec = true
system("cat", "/proc/self/fd/#{f.fileno}") # cat: /proc/self/fd/3: No such file or directory
f.closed?                #=> false

Ruby sets close-on-exec flags of all file descriptors by default since Ruby 2.0.0. So you don’t need to set by yourself. Also, unsetting a close-on-exec flag can cause file descriptor leak if another thread use fork() and exec() (via system() method for example). If you really needs file descriptor inheritance to child process, use spawn()‘s argument such as fd=>fd.

ios.close_on_exec? → true or false

io.c View on GitHub

          
            static VALUE
rb_io_close_on_exec_p(VALUE io)
{
    rb_io_t *fptr;
    VALUE write_io;
    int fd, ret;

    write_io = GetWriteIO(io);
    if (io != write_io) {
        GetOpenFile(write_io, fptr);
        if (fptr && 0 <= (fd = fptr->fd)) {
            if ((ret = fcntl(fd, F_GETFD)) == -1) rb_sys_fail_path(fptr->pathv);
            if (!(ret & FD_CLOEXEC)) return Qfalse;
        }
    }

    GetOpenFile(io, fptr);
    if (fptr && 0 <= (fd = fptr->fd)) {
        if ((ret = fcntl(fd, F_GETFD)) == -1) rb_sys_fail_path(fptr->pathv);
        if (!(ret & FD_CLOEXEC)) return Qfalse;
    }
    return Qtrue;
}

Returns true if ios will be closed on exec.

f = open("/dev/null")
f.close_on_exec?                 #=> false
f.close_on_exec = true
f.close_on_exec?                 #=> true
f.close_on_exec = false
f.close_on_exec?                 #=> false

ios.close_read → nil

io.c View on GitHub

          
            static VALUE
rb_io_close_read(VALUE io)
{
    rb_io_t *fptr;
    VALUE write_io;

    fptr = rb_io_get_fptr(rb_io_taint_check(io));
    if (fptr->fd < 0) return Qnil;
    if (is_socket(fptr->fd, fptr->pathv)) {
#ifndef SHUT_RD
# define SHUT_RD 0
#endif
        if (shutdown(fptr->fd, SHUT_RD) < 0)
            rb_sys_fail_path(fptr->pathv);
        fptr->mode &= ~FMODE_READABLE;
        if (!(fptr->mode & FMODE_WRITABLE))
            return rb_io_close(io);
        return Qnil;
    }

    write_io = GetWriteIO(io);
    if (io != write_io) {
        rb_io_t *wfptr;
        wfptr = rb_io_get_fptr(rb_io_taint_check(write_io));
        wfptr->pid = fptr->pid;
        fptr->pid = 0;
        RFILE(io)->fptr = wfptr;
        /* bind to write_io temporarily to get rid of memory/fd leak */
        fptr->tied_io_for_writing = 0;
        RFILE(write_io)->fptr = fptr;
        rb_io_fptr_cleanup(fptr, FALSE);
        /* should not finalize fptr because another thread may be reading it */
        return Qnil;
    }

    if ((fptr->mode & (FMODE_DUPLEX|FMODE_WRITABLE)) == FMODE_WRITABLE) {
        rb_raise(rb_eIOError, "closing non-duplex IO for reading");
    }
    return rb_io_close(io);
}

Closes the read end of a duplex I/O stream (i.e., one that contains both a read and a write stream, such as a pipe). Will raise an IOError if the stream is not duplexed.

f = IO.popen("/bin/sh","r+")
f.close_read
f.readlines

produces:

prog.rb:3:in `readlines': not opened for reading (IOError)
 from prog.rb:3

Calling this method on closed IO object is just ignored since Ruby 2.3.

ios.close_write → nil

io.c View on GitHub

          
            static VALUE
rb_io_close_write(VALUE io)
{
    rb_io_t *fptr;
    VALUE write_io;

    write_io = GetWriteIO(io);
    fptr = rb_io_get_fptr(rb_io_taint_check(write_io));
    if (fptr->fd < 0) return Qnil;
    if (is_socket(fptr->fd, fptr->pathv)) {
#ifndef SHUT_WR
# define SHUT_WR 1
#endif
        if (shutdown(fptr->fd, SHUT_WR) < 0)
            rb_sys_fail_path(fptr->pathv);
        fptr->mode &= ~FMODE_WRITABLE;
        if (!(fptr->mode & FMODE_READABLE))
            return rb_io_close(write_io);
        return Qnil;
    }

    if ((fptr->mode & (FMODE_DUPLEX|FMODE_READABLE)) == FMODE_READABLE) {
        rb_raise(rb_eIOError, "closing non-duplex IO for writing");
    }

    if (io != write_io) {
        fptr = rb_io_get_fptr(rb_io_taint_check(io));
        fptr->tied_io_for_writing = 0;
    }
    rb_io_close(write_io);
    return Qnil;
}

Closes the write end of a duplex I/O stream (i.e., one that contains both a read and a write stream, such as a pipe). Will raise an IOError if the stream is not duplexed.

f = IO.popen("/bin/sh","r+")
f.close_write
f.print "nowhere"

produces:

prog.rb:3:in `write': not opened for writing (IOError)
 from prog.rb:3:in `print'
 from prog.rb:3

Calling this method on closed IO object is just ignored since Ruby 2.3.

ios.closed? → true or false

io.c View on GitHub

          
            static VALUE
rb_io_closed(VALUE io)
{
    rb_io_t *fptr;
    VALUE write_io;
    rb_io_t *write_fptr;

    write_io = GetWriteIO(io);
    if (io != write_io) {
        write_fptr = RFILE(write_io)->fptr;
        if (write_fptr && 0 <= write_fptr->fd) {
            return Qfalse;
        }
    }

    fptr = rb_io_get_fptr(io);
    return RBOOL(0 > fptr->fd);
}

Returns true if ios is completely closed (for duplex streams, both reader and writer), false otherwise.

f = File.new("testfile")
f.close         #=> nil
f.closed?       #=> true
f = IO.popen("/bin/sh","r+")
f.close_write   #=> nil
f.closed?       #=> false
f.close_read    #=> nil
f.closed?       #=> true

io.console_mode → mode

ext/io/console/console.c View on GitHub

          
            static VALUE
console_conmode_get(VALUE io)
{
    conmode t;
    rb_io_t *fptr;
    int fd;

    GetOpenFile(io, fptr);
    fd = GetReadFD(fptr);
    if (!getattr(fd, &t)) sys_fail_fptr(fptr);

    return conmode_new(cConmode, &t);
}

Returns a data represents the current console mode.

You must require ‘io/console’ to use this method.

io.console_mode = mode

ext/io/console/console.c View on GitHub

          
            static VALUE
console_conmode_set(VALUE io, VALUE mode)
{
    conmode *t, r;
    rb_io_t *fptr;
    int fd;

    TypedData_Get_Struct(mode, conmode, &conmode_type, t);
    r = *t;
    GetOpenFile(io, fptr);
    fd = GetReadFD(fptr);
    if (!setattr(fd, &r)) sys_fail_fptr(fptr);

    return mode;
}

Sets the console mode to mode.

You must require ‘io/console’ to use this method.

io.cooked {|io| }

ext/io/console/console.c View on GitHub

          
            static VALUE
console_cooked(VALUE io)
{
    return ttymode(io, rb_yield, io, set_cookedmode, NULL);
}

Yields self within cooked mode.

STDIN.cooked(&:gets)

will read and return a line with echo back and line editing.

You must require ‘io/console’ to use this method.

io.cooked!

ext/io/console/console.c View on GitHub

          
            static VALUE
console_set_cooked(VALUE io)
{
    conmode t;
    rb_io_t *fptr;
    int fd;

    GetOpenFile(io, fptr);
    fd = GetReadFD(fptr);
    if (!getattr(fd, &t)) sys_fail_fptr(fptr);
    set_cookedmode(&t, NULL);
    if (!setattr(fd, &t)) sys_fail_fptr(fptr);
    return io;
}

Enables cooked mode.

If the terminal mode needs to be back, use io.cooked { … }.

You must require ‘io/console’ to use this method.

cursor

ext/io/console/console.c View on GitHub

          
            static VALUE
console_cursor_pos(VALUE io)
{
    rb_io_t *fptr;
    int fd;
    rb_console_size_t ws;

    GetOpenFile(io, fptr);
    fd = GetWriteFD(fptr);
    if (!GetConsoleScreenBufferInfo((HANDLE)rb_w32_get_osfhandle(fd), &ws)) {
        rb_syserr_fail(LAST_ERROR, 0);
    }
    return rb_assoc_new(UINT2NUM(ws.dwCursorPosition.Y), UINT2NUM(ws.dwCursorPosition.X));
}

No documentation available

cursor=(p1)

ext/io/console/console.c View on GitHub

          
            endif

static VALUE
console_cursor_set(VALUE io, VALUE cpos)
{
    cpos = rb_convert_type(cpos, T_ARRAY, "Array", "to_ary");
    if (RARRAY_LEN(cpos) != 2) rb_raise(rb_eArgError, "expected 2D coordinate");
    return console_goto(io, RARRAY_AREF(cpos, 0), RARRAY_AREF(cpos, 1));
}

No documentation available

cursor_down(p1)

ext/io/console/console.c View on GitHub

          
            static VALUE
console_cursor_down(VALUE io, VALUE val)
{
    return console_move(io, +NUM2INT(val), 0);
}

No documentation available

cursor_left(p1)

ext/io/console/console.c View on GitHub

          
            static VALUE
console_cursor_left(VALUE io, VALUE val)
{
    return console_move(io, 0, -NUM2INT(val));
}

No documentation available

cursor_right(p1)

ext/io/console/console.c View on GitHub

          
            static VALUE
console_cursor_right(VALUE io, VALUE val)
{
    return console_move(io, 0, +NUM2INT(val));
}

No documentation available

cursor_up(p1)

ext/io/console/console.c View on GitHub

          
            static VALUE
console_cursor_up(VALUE io, VALUE val)
{
    return console_move(io, -NUM2INT(val), 0);
}

No documentation available

ios.each(sep=$/ [, getline_args]) {|line| block } → ios

ios.each(limit [, getline_args]) {|line| block } → ios

ios.each(sep, limit [, getline_args]) {|line| block } → ios

ios.each(...) → an_enumerator

io.c View on GitHub

          
            static VALUE
rb_io_each_line(int argc, VALUE *argv, VALUE io)
{
    VALUE str;
    struct getline_arg args;

    RETURN_ENUMERATOR(io, argc, argv);
    prepare_getline_args(argc, argv, &args, io);
    if (args.limit == 0)
        rb_raise(rb_eArgError, "invalid limit: 0 for each_line");
    while (!NIL_P(str = rb_io_getline_1(args.rs, args.limit, args.chomp, io))) {
        rb_yield(str);
    }
    return io;
}

Executes the block for every line in ios, where lines are separated by sep. ios must be opened for reading or an IOError will be raised.

If no block is given, an enumerator is returned instead.

f = File.new("testfile")
f.each {|line| puts "#{f.lineno}: #{line}" }

produces:

1: This is line one
2: This is line two
3: This is line three
4: And so on...

See IO.readlines for details about getline_args.

ios.each_byte {|byte| block } → ios

ios.each_byte → an_enumerator

io.c View on GitHub

          
            static VALUE
rb_io_each_byte(VALUE io)
{
    rb_io_t *fptr;

    RETURN_ENUMERATOR(io, 0, 0);
    GetOpenFile(io, fptr);

    do {
        while (fptr->rbuf.len > 0) {
            char *p = fptr->rbuf.ptr + fptr->rbuf.off++;
            fptr->rbuf.len--;
            rb_yield(INT2FIX(*p & 0xff));
            rb_io_check_byte_readable(fptr);
            errno = 0;
        }
        READ_CHECK(fptr);
    } while (io_fillbuf(fptr) >= 0);
    return io;
}

Calls the given block once for each byte (0..255) in ios, passing the byte as an argument. The stream must be opened for reading or an IOError will be raised.

If no block is given, an enumerator is returned instead.

f = File.new("testfile")
checksum = 0
f.each_byte {|x| checksum ^= x }   #=> #<File:testfile>
checksum                           #=> 12

ios.each_char {|c| block } → ios

ios.each_char → an_enumerator

io.c View on GitHub

          
            static VALUE
rb_io_each_char(VALUE io)
{
    rb_io_t *fptr;
    rb_encoding *enc;
    VALUE c;

    RETURN_ENUMERATOR(io, 0, 0);
    GetOpenFile(io, fptr);
    rb_io_check_char_readable(fptr);

    enc = io_input_encoding(fptr);
    READ_CHECK(fptr);
    while (!NIL_P(c = io_getc(fptr, enc))) {
        rb_yield(c);
    }
    return io;
}

Calls the given block once for each character in ios, passing the character as an argument. The stream must be opened for reading or an IOError will be raised.

If no block is given, an enumerator is returned instead.

f = File.new("testfile")
f.each_char {|c| print c, ' ' }   #=> #<File:testfile>

ios.each_codepoint {|c| block } → ios

ios.each_codepoint → an_enumerator

io.c View on GitHub

          
            static VALUE
rb_io_each_codepoint(VALUE io)
{
    rb_io_t *fptr;
    rb_encoding *enc;
    unsigned int c;
    int r, n;

    RETURN_ENUMERATOR(io, 0, 0);
    GetOpenFile(io, fptr);
    rb_io_check_char_readable(fptr);

    READ_CHECK(fptr);
    if (NEED_READCONV(fptr)) {
        SET_BINARY_MODE(fptr);
        r = 1;         /* no invalid char yet */
        for (;;) {
            make_readconv(fptr, 0);
            for (;;) {
                if (fptr->cbuf.len) {
                    if (fptr->encs.enc)
                        r = rb_enc_precise_mbclen(fptr->cbuf.ptr+fptr->cbuf.off,
                                                  fptr->cbuf.ptr+fptr->cbuf.off+fptr->cbuf.len,
                                                  fptr->encs.enc);
                    else
                        r = ONIGENC_CONSTRUCT_MBCLEN_CHARFOUND(1);
                    if (!MBCLEN_NEEDMORE_P(r))
                        break;
                    if (fptr->cbuf.len == fptr->cbuf.capa) {
                        rb_raise(rb_eIOError, "too long character");
                    }
                }
                if (more_char(fptr) == MORE_CHAR_FINISHED) {
                    clear_readconv(fptr);
                    if (!MBCLEN_CHARFOUND_P(r)) {
                        enc = fptr->encs.enc;
                        goto invalid;
                    }
                    return io;
                }
            }
            if (MBCLEN_INVALID_P(r)) {
                enc = fptr->encs.enc;
                goto invalid;
            }
            n = MBCLEN_CHARFOUND_LEN(r);
            if (fptr->encs.enc) {
                c = rb_enc_codepoint(fptr->cbuf.ptr+fptr->cbuf.off,
                                     fptr->cbuf.ptr+fptr->cbuf.off+fptr->cbuf.len,
                                     fptr->encs.enc);
            }
            else {
                c = (unsigned char)fptr->cbuf.ptr[fptr->cbuf.off];
            }
            fptr->cbuf.off += n;
            fptr->cbuf.len -= n;
            rb_yield(UINT2NUM(c));
            rb_io_check_byte_readable(fptr);
        }
    }
    NEED_NEWLINE_DECORATOR_ON_READ_CHECK(fptr);
    enc = io_input_encoding(fptr);
    while (io_fillbuf(fptr) >= 0) {
        r = rb_enc_precise_mbclen(fptr->rbuf.ptr+fptr->rbuf.off,
                                  fptr->rbuf.ptr+fptr->rbuf.off+fptr->rbuf.len, enc);
        if (MBCLEN_CHARFOUND_P(r) &&
            (n = MBCLEN_CHARFOUND_LEN(r)) <= fptr->rbuf.len) {
            c = rb_enc_codepoint(fptr->rbuf.ptr+fptr->rbuf.off,
                                 fptr->rbuf.ptr+fptr->rbuf.off+fptr->rbuf.len, enc);
            fptr->rbuf.off += n;
            fptr->rbuf.len -= n;
            rb_yield(UINT2NUM(c));
        }
        else if (MBCLEN_INVALID_P(r)) {
            goto invalid;
        }
        else if (MBCLEN_NEEDMORE_P(r)) {
            char cbuf[8], *p = cbuf;
            int more = MBCLEN_NEEDMORE_LEN(r);
            if (more > numberof(cbuf)) goto invalid;
            more += n = fptr->rbuf.len;
            if (more > numberof(cbuf)) goto invalid;
            while ((n = (int)read_buffered_data(p, more, fptr)) > 0 &&
                   (p += n, (more -= n) > 0)) {
                if (io_fillbuf(fptr) < 0) goto invalid;
                if ((n = fptr->rbuf.len) > more) n = more;
            }
            r = rb_enc_precise_mbclen(cbuf, p, enc);
            if (!MBCLEN_CHARFOUND_P(r)) goto invalid;
            c = rb_enc_codepoint(cbuf, p, enc);
            rb_yield(UINT2NUM(c));
        }
        else {
            continue;
        }
        rb_io_check_byte_readable(fptr);
    }
    return io;

  invalid:
    rb_raise(rb_eArgError, "invalid byte sequence in %s", rb_enc_name(enc));
    UNREACHABLE_RETURN(Qundef);
}

Passes the Integer ordinal of each character in ios, passing the codepoint as an argument. The stream must be opened for reading or an IOError will be raised.

If no block is given, an enumerator is returned instead.

ios.each_line(sep=$/ [, getline_args]) {|line| block } → ios

ios.each_line(limit [, getline_args]) {|line| block } → ios

ios.each_line(sep, limit [, getline_args]) {|line| block } → ios

ios.each_line(...) → an_enumerator

io.c View on GitHub

An alias for each

io.echo = flag

ext/io/console/console.c View on GitHub

          
            static VALUE
console_set_echo(VALUE io, VALUE f)
{
    conmode t;
    rb_io_t *fptr;
    int fd;

    GetOpenFile(io, fptr);
    fd = GetReadFD(fptr);
    if (!getattr(fd, &t)) sys_fail_fptr(fptr);
    if (RTEST(f))
        set_echo(&t, NULL);
    else
        set_noecho(&t, NULL);
    if (!setattr(fd, &t)) sys_fail_fptr(fptr);
    return io;
}

Enables/disables echo back. On some platforms, all combinations of this flags and raw/cooked mode may not be valid.

You must require ‘io/console’ to use this method.

io.echo? → true or false

ext/io/console/console.c View on GitHub

          
            static VALUE
console_echo_p(VALUE io)
{
    conmode t;
    rb_io_t *fptr;
    int fd;

    GetOpenFile(io, fptr);
    fd = GetReadFD(fptr);
    if (!getattr(fd, &t)) sys_fail_fptr(fptr);
    return echo_p(&t) ? Qtrue : Qfalse;
}

Returns true if echo back is enabled.

You must require ‘io/console’ to use this method.

eof → true or false

io.c View on GitHub

          
            VALUE
rb_io_eof(VALUE io)
{
    rb_io_t *fptr;

    GetOpenFile(io, fptr);
    rb_io_check_char_readable(fptr);

    if (READ_CHAR_PENDING(fptr)) return Qfalse;
    if (READ_DATA_PENDING(fptr)) return Qfalse;
    READ_CHECK(fptr);
#if RUBY_CRLF_ENVIRONMENT
    if (!NEED_READCONV(fptr) && NEED_NEWLINE_DECORATOR_ON_READ(fptr)) {
        return RBOOL(eof(fptr->fd));;
    }
#endif
    return RBOOL(io_fillbuf(fptr) < 0);
}

Returns true if the stream is positioned at its end, false otherwise; see Position:

f = File.open('t.txt')
f.eof           # => false
f.seek(0, :END) # => 0
f.eof           # => true

Raises an exception unless the stream is opened for reading; see Mode.

If self is a stream such as pipe or socket, this method blocks until the other end sends some data or closes it:

r, w = IO.pipe
Thread.new { sleep 1; w.close }
r.eof? # => true # After 1-second wait.

r, w = IO.pipe
Thread.new { sleep 1; w.puts "a" }
r.eof?  # => false # After 1-second wait.

r, w = IO.pipe
r.eof?  # blocks forever

Note that this method reads data to the input byte buffer. So IO#sysread may not behave as you intend with IO#eof?, unless you call IO#rewind first (which is not available for some streams).

I#eof? is an alias for IO#eof.

eof?

io.c View on GitHub

An alias for eof

erase_line(p1)

ext/io/console/console.c View on GitHub

          
            static VALUE
console_erase_line(VALUE io, VALUE val)
{
    rb_io_t *fptr;
    HANDLE h;
    rb_console_size_t ws;
    COORD *pos = &ws.dwCursorPosition;
    DWORD w;
    int mode = mode_in_range(val, 2, "line erase");

    GetOpenFile(io, fptr);
    h = (HANDLE)rb_w32_get_osfhandle(GetWriteFD(fptr));
    if (!GetConsoleScreenBufferInfo(h, &ws)) {
        rb_syserr_fail(LAST_ERROR, 0);
    }
    w = winsize_col(&ws);
    switch (mode) {
      case 0:                   /* after cursor */
        w -= pos->X;
        break;
      case 1:                   /* before *and* cursor */
        w = pos->X + 1;
        pos->X = 0;
        break;
      case 2:                   /* entire line */
        pos->X = 0;
        break;
    }
    constat_clear(h, ws.wAttributes, w, *pos);
    return io;
}

No documentation available

erase_screen(p1)

ext/io/console/console.c View on GitHub

          
            static VALUE
console_erase_screen(VALUE io, VALUE val)
{
    rb_io_t *fptr;
    HANDLE h;
    rb_console_size_t ws;
    COORD *pos = &ws.dwCursorPosition;
    DWORD w;
    int mode = mode_in_range(val, 3, "screen erase");

    GetOpenFile(io, fptr);
    h = (HANDLE)rb_w32_get_osfhandle(GetWriteFD(fptr));
    if (!GetConsoleScreenBufferInfo(h, &ws)) {
        rb_syserr_fail(LAST_ERROR, 0);
    }
    w = winsize_col(&ws);
    switch (mode) {
      case 0:   /* erase after cursor */
        w = (w * (ws.srWindow.Bottom - pos->Y + 1) - pos->X);
        break;
      case 1:   /* erase before *and* cursor */
        w = (w * (pos->Y - ws.srWindow.Top) + pos->X + 1);
        pos->X = 0;
        pos->Y = ws.srWindow.Top;
        break;
      case 2:   /* erase entire screen */
        w = (w * winsize_row(&ws));
        pos->X = 0;
        pos->Y = ws.srWindow.Top;
        break;
      case 3:   /* erase entire screen */
        w = (w * ws.dwSize.Y);
        pos->X = 0;
        pos->Y = 0;
        break;
    }
    constat_clear(h, ws.wAttributes, w, *pos);
    return io;
}

No documentation available

IO#expect(pattern,timeout=9999999) → Array

IO#expect(pattern,timeout=9999999) { |result| ... } → nil

ext/pty/lib/expect.rb View on GitHub

          
            # File tmp/rubies/ruby-3.1.3/ext/pty/lib/expect.rb, line 33
def expect(pat,timeout=9999999)
  buf = ''.dup
  case pat
  when String
    e_pat = Regexp.new(Regexp.quote(pat))
  when Regexp
    e_pat = pat
  else
    raise TypeError, "unsupported pattern class: #{pat.class}"
  end
  @unusedBuf ||= ''
  while true
    if not @unusedBuf.empty?
      c = @unusedBuf.slice!(0)
    elsif !IO.select([self],nil,nil,timeout) or eof? then
      result = nil
      @unusedBuf = buf
      break
    else
      c = getc
    end
    buf << c
    if $expect_verbose
      STDOUT.print c
      STDOUT.flush
    end
    if mat=e_pat.match(buf) then
      result = [buf,*mat.captures]
      break
    end
  end
  if block_given? then
    yield result
  else
    return result
  end
  nil
end

Reads from the IO until the given pattern matches or the timeout is over.

It returns an array with the read buffer, followed by the matches. If a block is given, the result is yielded to the block and returns nil.

When called without a block, it waits until the input that matches the given pattern is obtained from the IO or the time specified as the timeout passes. An array is returned when the pattern is obtained from the IO. The first element of the array is the entire string obtained from the IO until the pattern matches, followed by elements indicating which the pattern which matched to the anchor in the regular expression.

The optional timeout parameter defines, in seconds, the total time to wait for the pattern. If the timeout expires or eof is found, nil is returned or yielded. However, the buffer in a timeout session is kept for the next expect call. The default timeout is 9999999 seconds.

io.external_encoding → encoding

io.c View on GitHub

          
            static VALUE
rb_io_external_encoding(VALUE io)
{
    rb_io_t *fptr = RFILE(rb_io_taint_check(io))->fptr;

    if (fptr->encs.enc2) {
        return rb_enc_from_encoding(fptr->encs.enc2);
    }
    if (fptr->mode & FMODE_WRITABLE) {
        if (fptr->encs.enc)
            return rb_enc_from_encoding(fptr->encs.enc);
        return Qnil;
    }
    return rb_enc_from_encoding(io_read_encoding(fptr));
}

Returns the Encoding object that represents the encoding of the file. If io is in write mode and no encoding is specified, returns nil.

ios.fcntl(integer_cmd, arg) → integer

io.c View on GitHub

          
            static VALUE
rb_io_fcntl(int argc, VALUE *argv, VALUE io)
{
    VALUE req, arg;

    rb_scan_args(argc, argv, "11", &req, &arg);
    return rb_fcntl(io, req, arg);
}

Provides a mechanism for issuing low-level commands to control or query file-oriented I/O streams. Arguments and results are platform dependent. If arg is a number, its value is passed directly. If it is a string, it is interpreted as a binary sequence of bytes (Array#pack might be a useful way to build this string). On Unix platforms, see fcntl(2) for details. Not implemented on all platforms.

fdatasync → 0

io.c View on GitHub

          
            static VALUE
rb_io_fdatasync(VALUE io)
{
    rb_io_t *fptr;

    io = GetWriteIO(io);
    GetOpenFile(io, fptr);

    if (io_fflush(fptr) < 0)
        rb_sys_fail_on_write(fptr);

    if ((int)rb_thread_io_blocking_region(nogvl_fdatasync, fptr, fptr->fd) == 0)
        return INT2FIX(0);

    /* fall back */
    return rb_io_fsync(io);
}

Immediately writes to disk all data buffered in the stream, via the operating system’s: fdatasync(2), if supported, otherwise via fsync(2), if supported; otherwise raises an exception.

fileno → integer

io.c View on GitHub

          
            static VALUE
rb_io_fileno(VALUE io)
{
    rb_io_t *fptr = RFILE(io)->fptr;
    int fd;

    rb_io_check_closed(fptr);
    fd = fptr->fd;
    return INT2FIX(fd);
}

Returns the integer file descriptor for the stream:

$stdin.fileno             # => 0
$stdout.fileno            # => 1
$stderr.fileno            # => 2
File.open('t.txt').fileno # => 10

IO#to_i is an alias for IO#fileno.

flush → self

io.c View on GitHub

          
            VALUE
rb_io_flush(VALUE io)
{
    return rb_io_flush_raw(io, 1);
}

Flushes data buffered in self to the operating system (but does not necessarily flush data buffered in the operating system):

$stdout.print 'no newline' # Not necessarily flushed.
$stdout.flush              # Flushed.

fsync → 0

io.c View on GitHub

          
            static VALUE
rb_io_fsync(VALUE io)
{
    rb_io_t *fptr;

    io = GetWriteIO(io);
    GetOpenFile(io, fptr);

    if (io_fflush(fptr) < 0)
        rb_sys_fail_on_write(fptr);
    if ((int)rb_thread_io_blocking_region(nogvl_fsync, fptr, fptr->fd) < 0)
        rb_sys_fail_path(fptr->pathv);
    return INT2FIX(0);
}

Immediately writes to disk all data buffered in the stream, via the operating system’s fsync(2).

Note this difference:

IO#sync=: Ensures that data is flushed from the stream’s internal buffers, but does not guarantee that the operating system actually writes the data to disk.
IO#fsync: Ensures both that data is flushed from internal buffers, and that data is written to disk.

Raises an exception if the operating system does not support fsync(2).

ios.getbyte → integer or nil

io.c View on GitHub

          
            VALUE
rb_io_getbyte(VALUE io)
{
    rb_io_t *fptr;
    int c;

    GetOpenFile(io, fptr);
    rb_io_check_byte_readable(fptr);
    READ_CHECK(fptr);
    VALUE r_stdout = rb_ractor_stdout();
    if (fptr->fd == 0 && (fptr->mode & FMODE_TTY) && RB_TYPE_P(r_stdout, T_FILE)) {
        rb_io_t *ofp;
        GetOpenFile(r_stdout, ofp);
        if (ofp->mode & FMODE_TTY) {
            rb_io_flush(r_stdout);
        }
    }
    if (io_fillbuf(fptr) < 0) {
        return Qnil;
    }
    fptr->rbuf.off++;
    fptr->rbuf.len--;
    c = (unsigned char)fptr->rbuf.ptr[fptr->rbuf.off-1];
    return INT2FIX(c & 0xff);
}

Gets the next 8-bit byte (0..255) from ios. Returns nil if called at end of file.

f = File.new("testfile")
f.getbyte   #=> 84
f.getbyte   #=> 104

ios.getc → string or nil

io.c View on GitHub

          
            static VALUE
rb_io_getc(VALUE io)
{
    rb_io_t *fptr;
    rb_encoding *enc;

    GetOpenFile(io, fptr);
    rb_io_check_char_readable(fptr);

    enc = io_input_encoding(fptr);
    READ_CHECK(fptr);
    return io_getc(fptr, enc);
}

Reads a one-character string from ios. Returns nil if called at end of file.

f = File.new("testfile")
f.getc   #=> "h"
f.getc   #=> "e"

io.getch(min: nil, time: nil, intr: nil) → char

ext/io/console/console.c View on GitHub

          
            static VALUE
console_getch(int argc, VALUE *argv, VALUE io)
{
    rawmode_arg_t opts, *optp = rawmode_opt(&argc, argv, 0, 0, &opts);
#ifndef _WIN32
    return ttymode(io, getc_call, io, set_rawmode, optp);
#else
    rb_io_t *fptr;
    VALUE str;
    wint_t c;
    int len;
    char buf[8];
    wint_t wbuf[2];
# ifndef HAVE_RB_IO_WAIT
    struct timeval *to = NULL, tv;
# else
    VALUE timeout = Qnil;
# endif

    GetOpenFile(io, fptr);
    if (optp) {
        if (optp->vtime) {
# ifndef HAVE_RB_IO_WAIT
            to = &tv;
# else
            struct timeval tv;
# endif
            tv.tv_sec = optp->vtime / 10;
            tv.tv_usec = (optp->vtime % 10) * 100000;
# ifdef HAVE_RB_IO_WAIT
            timeout = rb_fiber_scheduler_make_timeout(&tv);
# endif
        }
        switch (optp->vmin) {
          case 1: /* default */
            break;
          case 0: /* return nil when timed out */
            if (optp->vtime) break;
            /* fallthru */
          default:
            rb_warning("min option larger than 1 ignored");
        }
        if (optp->intr) {
# ifndef HAVE_RB_IO_WAIT
            int w = rb_wait_for_single_fd(fptr->fd, RB_WAITFD_IN, to);
            if (w < 0) rb_eof_error();
            if (!(w & RB_WAITFD_IN)) return Qnil;
# else
            VALUE result = rb_io_wait(io, RB_INT2NUM(RUBY_IO_READABLE), timeout);
            if (!RTEST(result)) return Qnil;
# endif
        }
        else if (optp->vtime) {
            rb_warning("Non-zero vtime option ignored if intr flag is unset");
        }
    }
    len = (int)(VALUE)rb_thread_call_without_gvl(nogvl_getch, wbuf, RUBY_UBF_IO, 0);
    switch (len) {
      case 0:
        return Qnil;
      case 2:
        buf[0] = (char)wbuf[0];
        c = wbuf[1];
        len = 1;
        do {
            buf[len++] = (unsigned char)c;
        } while ((c >>= CHAR_BIT) && len < (int)sizeof(buf));
        return rb_str_new(buf, len);
      default:
        c = wbuf[0];
        len = rb_uv_to_utf8(buf, c);
        str = rb_utf8_str_new(buf, len);
        return rb_str_conv_enc(str, NULL, rb_default_external_encoding());
    }
#endif
}

Reads and returns a character in raw mode.

See IO#raw for details on the parameters.

You must require ‘io/console’ to use this method.

io.getpass(prompt=nil) → string

ext/io/console/console.c View on GitHub

          
            static VALUE
console_getpass(int argc, VALUE *argv, VALUE io)
{
    VALUE str, wio;

    rb_check_arity(argc, 0, 1);
    wio = rb_io_get_write_io(io);
    if (wio == io && io == rb_stdin) wio = rb_stderr;
    prompt(argc, argv, wio);
    str = rb_ensure(getpass_call, io, puts_call, wio);
    return str_chomp(str);
}

Reads and returns a line without echo back. Prints prompt unless it is nil.

The newline character that terminates the read line is removed from the returned string, see String#chomp!.

You must require ‘io/console’ to use this method.

gets(sep = $/, **getline_opts) → string or nil

gets(limit, **getline_opts) → string or nil

gets(sep, limit, **getline_opts) → string or nil

io.c View on GitHub

          
            static VALUE
rb_io_gets_m(int argc, VALUE *argv, VALUE io)
{
    VALUE str;

    str = rb_io_getline(argc, argv, io);
    rb_lastline_set(str);

    return str;
}

Reads and returns data from the stream; assigns the return value to $_.

With no arguments given, returns the next line as determined by line separator $/, or nil if none:

f = File.open('t.txt')
f.gets # => "This is line one.\n"
$_     # => "This is line one.\n"
f.gets # => "This is the second line.\n"
f.gets # => "This is the third line.\n"
f.gets # => nil

With string argument sep given, but not argument limit, returns the next line as determined by line separator sep, or nil if none:

f = File.open('t.txt')
f.gets(' is') # => "This is"
f.gets(' is') # => " line one.\nThis is"
f.gets(' is') # => " the second line.\nThis is"
f.gets(' is') # => " the third line.\n"
f.gets(' is') # => nil

Note two special values for sep:

nil: The entire stream is read and returned.
'' (empty string): The next “paragraph” is read and returned, the paragraph separator being two successive line separators.

With integer argument limit given, returns up to limit+1 bytes:

# Text with 1-byte characters.
File.open('t.txt') {|f| f.gets(1) } # => "T"
File.open('t.txt') {|f| f.gets(2) } # => "Th"
File.open('t.txt') {|f| f.gets(3) } # => "Thi"
File.open('t.txt') {|f| f.gets(4) } # => "This"
# No more than one line.
File.open('t.txt') {|f| f.gets(17) } # => "This is line one."
File.open('t.txt') {|f| f.gets(18) } # => "This is line one.\n"
File.open('t.txt') {|f| f.gets(19) } # => "This is line one.\n"

# Text with 2-byte characters, which will not be split.
File.open('t.rus') {|f| f.gets(1).size } # => 1
File.open('t.rus') {|f| f.gets(2).size } # => 1
File.open('t.rus') {|f| f.gets(3).size } # => 2
File.open('t.rus') {|f| f.gets(4).size } # => 2

With arguments sep and limit, combines the two behaviors above:

Returns the next line as determined by line separator sep, or nil if none.
But returns no more than limit+1 bytes.

For all forms above, trailing optional keyword arguments may be given; see Getline Options:

f = File.open('t.txt')
# Chomp the lines.
f.gets(chomp: true) # => "This is line one."
f.gets(chomp: true) # => "This is the second line."
f.gets(chomp: true) # => "This is the third line."
f.gets(chomp: true) # => nil

goto(p1, p2)

ext/io/console/console.c View on GitHub

          
            _WIN32
static VALUE
console_goto(VALUE io, VALUE y, VALUE x)
{
    rb_io_t *fptr;
    int fd;
    COORD pos;

    GetOpenFile(io, fptr);
    fd = GetWriteFD(fptr);
    pos.X = NUM2UINT(x);
    pos.Y = NUM2UINT(y);
    if (!SetConsoleCursorPosition((HANDLE)rb_w32_get_osfhandle(fd), pos)) {
        rb_syserr_fail(LAST_ERROR, 0);
    }
    return io;
}

No documentation available

goto_column(p1)

ext/io/console/console.c View on GitHub

          
            static VALUE
console_goto_column(VALUE io, VALUE val)
{
    rb_io_t *fptr;
    HANDLE h;
    rb_console_size_t ws;
    COORD *pos = &ws.dwCursorPosition;

    GetOpenFile(io, fptr);
    h = (HANDLE)rb_w32_get_osfhandle(GetWriteFD(fptr));
    if (!GetConsoleScreenBufferInfo(h, &ws)) {
        rb_syserr_fail(LAST_ERROR, 0);
    }
    pos->X = NUM2INT(val);
    if (!SetConsoleCursorPosition(h, *pos)) {
        rb_syserr_fail(LAST_ERROR, 0);
    }
    return io;
}

No documentation available

io.iflush

ext/io/console/console.c View on GitHub

          
            static VALUE
console_iflush(VALUE io)
{
    rb_io_t *fptr;
    int fd;

    GetOpenFile(io, fptr);
    fd = GetReadFD(fptr);
#if defined HAVE_TERMIOS_H || defined HAVE_TERMIO_H
    if (tcflush(fd, TCIFLUSH)) sys_fail_fptr(fptr);
#endif
    (void)fd;
    return io;
}

Flushes input buffer in kernel.

You must require ‘io/console’ to use this method.

inspect → string

io.c View on GitHub

          
            static VALUE
rb_io_inspect(VALUE obj)
{
    rb_io_t *fptr;
    VALUE result;
    static const char closed[] = " (closed)";

    fptr = RFILE(obj)->fptr;
    if (!fptr) return rb_any_to_s(obj);
    result = rb_str_new_cstr("#<");
    rb_str_append(result, rb_class_name(CLASS_OF(obj)));
    rb_str_cat2(result, ":");
    if (NIL_P(fptr->pathv)) {
        if (fptr->fd < 0) {
            rb_str_cat(result, closed+1, strlen(closed)-1);
        }
        else {
            rb_str_catf(result, "fd %d", fptr->fd);
        }
    }
    else {
        rb_str_append(result, fptr->pathv);
        if (fptr->fd < 0) {
            rb_str_cat(result, closed, strlen(closed));
        }
    }
    return rb_str_cat2(result, ">");
}

Returns a string representation of self:

f = File.open('t.txt')
f.inspect # => "#<File:t.txt>"

io.internal_encoding → encoding

io.c View on GitHub

          
            static VALUE
rb_io_internal_encoding(VALUE io)
{
    rb_io_t *fptr = RFILE(rb_io_taint_check(io))->fptr;

    if (!fptr->encs.enc2) return Qnil;
    return rb_enc_from_encoding(io_read_encoding(fptr));
}

Returns the Encoding of the internal string if conversion is specified. Otherwise returns nil.

ios.ioctl(integer_cmd, arg) → integer

io.c View on GitHub

          
            static VALUE
rb_io_ioctl(int argc, VALUE *argv, VALUE io)
{
    VALUE req, arg;

    rb_scan_args(argc, argv, "11", &req, &arg);
    return rb_ioctl(io, req, arg);
}

Provides a mechanism for issuing low-level commands to control or query I/O devices. Arguments and results are platform dependent. If arg is a number, its value is passed directly. If it is a string, it is interpreted as a binary sequence of bytes. On Unix platforms, see ioctl(2) for details. Not implemented on all platforms.

io.ioflush

ext/io/console/console.c View on GitHub

          
            static VALUE
console_ioflush(VALUE io)
{
    rb_io_t *fptr;
#if defined HAVE_TERMIOS_H || defined HAVE_TERMIO_H
    int fd1, fd2;
#endif

    GetOpenFile(io, fptr);
#if defined HAVE_TERMIOS_H || defined HAVE_TERMIO_H
    fd1 = GetReadFD(fptr);
    fd2 = GetWriteFD(fptr);
    if (fd2 != -1 && fd1 != fd2) {
        if (tcflush(fd1, TCIFLUSH)) sys_fail_fptr(fptr);
        if (tcflush(fd2, TCOFLUSH)) sys_fail_fptr(fptr);
    }
    else {
        if (tcflush(fd1, TCIOFLUSH)) sys_fail_fptr(fptr);
    }
#endif
    return io;
}

Flushes input and output buffers in kernel.

You must require ‘io/console’ to use this method.

ios.isatty → true or false

io.c View on GitHub

          
            static VALUE
rb_io_isatty(VALUE io)
{
    rb_io_t *fptr;

    GetOpenFile(io, fptr);
    return RBOOL(isatty(fptr->fd) != 0);
}

Returns true if ios is associated with a terminal device (tty), false otherwise.

File.new("testfile").isatty   #=> false
File.new("/dev/tty").isatty   #=> true

ios.lineno → integer

io.c View on GitHub

          
            static VALUE
rb_io_lineno(VALUE io)
{
    rb_io_t *fptr;

    GetOpenFile(io, fptr);
    rb_io_check_char_readable(fptr);
    return INT2NUM(fptr->lineno);
}

Returns the current line number in ios. The stream must be opened for reading. lineno counts the number of times gets is called rather than the number of newlines encountered. The two values will differ if gets is called with a separator other than newline.

Methods that use $/ like each, lines and readline will also increment lineno.

ios.lineno = integer → integer

io.c View on GitHub

          
            static VALUE
rb_io_set_lineno(VALUE io, VALUE lineno)
{
    rb_io_t *fptr;

    GetOpenFile(io, fptr);
    rb_io_check_char_readable(fptr);
    fptr->lineno = NUM2INT(lineno);
    return lineno;
}

Manually sets the current line number to the given value. $. is updated only on the next read.

f = File.new("testfile")
f.gets                     #=> "This is line one\n"
$.                         #=> 1
f.lineno = 1000
f.lineno                   #=> 1000
$.                         #=> 1         # lineno of last read
f.gets                     #=> "This is line two\n"
$.                         #=> 1001      # lineno of last read

io.noecho {|io| }

ext/io/console/console.c View on GitHub

          
            static VALUE
console_noecho(VALUE io)
{
    return ttymode(io, rb_yield, io, set_noecho, NULL);
}

Yields self with disabling echo back.

STDIN.noecho(&:gets)

will read and return a line without echo back.

You must require ‘io/console’ to use this method.

io.nonblock {|io| } → io

io.nonblock(boolean) {|io| } → io

ext/io/nonblock/nonblock.c View on GitHub

          
            static VALUE
rb_io_nonblock_block(int argc, VALUE *argv, VALUE io)
{
    int nb = 1;
    rb_io_t *fptr;
    int f, restore[2];

    GetOpenFile(io, fptr);
    if (argc > 0) {
        VALUE v;
        rb_scan_args(argc, argv, "01", &v);
        nb = RTEST(v);
    }
    f = io_nonblock_mode(fptr->fd);
    restore[0] = fptr->fd;
    restore[1] = f;
    if (!io_nonblock_set(fptr->fd, f, nb))
        return rb_yield(io);
    return rb_ensure(rb_yield, io, io_nonblock_restore, (VALUE)restore);
}

Yields self in non-blocking mode.

When false is given as an argument, self is yielded in blocking mode. The original mode is restored after the block is executed.

io.nonblock = boolean → boolean

ext/io/nonblock/nonblock.c View on GitHub

          
            static VALUE
rb_io_nonblock_set(VALUE io, VALUE nb)
{
    rb_io_t *fptr;
    GetOpenFile(io, fptr);
    if (RTEST(nb))
        rb_io_set_nonblock(fptr);
    else
        io_nonblock_set(fptr->fd, io_nonblock_mode(fptr->fd), RTEST(nb));
    return io;
}

Enables non-blocking mode on a stream when set to true, and blocking mode when set to false.

io.nonblock? → boolean

ext/io/nonblock/nonblock.c View on GitHub

          
            static VALUE
rb_io_nonblock_p(VALUE io)
{
    rb_io_t *fptr;
    GetOpenFile(io, fptr);
    if (io_nonblock_mode(fptr->fd) & O_NONBLOCK)
        return Qtrue;
    return Qfalse;
}

Returns true if an IO object is in non-blocking mode.

io.nread → int

ext/io/wait/wait.c View on GitHub

          
            static VALUE
io_nread(VALUE io)
{
    rb_io_t *fptr;
    int len;
    ioctl_arg n;

    GetOpenFile(io, fptr);
    rb_io_check_readable(fptr);
    len = rb_io_read_pending(fptr);
    if (len > 0) return INT2FIX(len);
    if (!FIONREAD_POSSIBLE_P(fptr->fd)) return INT2FIX(0);
    if (ioctl(fptr->fd, FIONREAD, &n)) return INT2FIX(0);
    if (n > 0) return ioctl_arg2num(n);
    return INT2FIX(0);
}

Returns number of bytes that can be read without blocking. Returns zero if no information available.

io.oflush

ext/io/console/console.c View on GitHub

          
            static VALUE
console_oflush(VALUE io)
{
    rb_io_t *fptr;
    int fd;

    GetOpenFile(io, fptr);
    fd = GetWriteFD(fptr);
#if defined HAVE_TERMIOS_H || defined HAVE_TERMIO_H
    if (tcflush(fd, TCOFLUSH)) sys_fail_fptr(fptr);
#endif
    (void)fd;
    return io;
}

Flushes output buffer in kernel.

You must require ‘io/console’ to use this method.

pathconf(p1)

ext/etc/etc.c View on GitHub

          
            static VALUE
io_pathconf(VALUE io, VALUE arg)
{
    int name;
    long ret;
    rb_io_t *fptr;

    name = NUM2INT(arg);

    GetOpenFile(io, fptr);

    errno = 0;
    ret = fpathconf(fptr->fd, name);
    if (ret == -1) {
        if (errno == 0) /* no limit */
            return Qnil;
        rb_sys_fail("fpathconf");
    }
    return LONG2NUM(ret);
}

Returns pathname configuration variable using fpathconf().

name should be a constant under Etc which begins with PC_.

The return value is an integer or nil. nil means indefinite limit. (fpathconf() returns -1 but errno is not set.)

require 'etc'
IO.pipe {|r, w|
  p w.pathconf(Etc::PC_PIPE_BUF) #=> 4096
}

pid → integer or nil

io.c View on GitHub

          
            static VALUE
rb_io_pid(VALUE io)
{
    rb_io_t *fptr;

    GetOpenFile(io, fptr);
    if (!fptr->pid)
        return Qnil;
    return PIDT2NUM(fptr->pid);
}

Returns the process ID of a child process associated with the stream, which will have been set by IO#popen, or nil if the stream was not created by IO#popen:

pipe = IO.popen("-")
if pipe
  $stderr.puts "In parent, child pid is #{pipe.pid}"
else
  $stderr.puts "In child, pid is #{$$}"
end

Output:

In child, pid is 26209
In parent, child pid is 26209

pos

io.c View on GitHub

An alias for tell

pos = new_position → new_position

io.c View on GitHub

          
            static VALUE
rb_io_set_pos(VALUE io, VALUE offset)
{
    rb_io_t *fptr;
    off_t pos;

    pos = NUM2OFFT(offset);
    GetOpenFile(io, fptr);
    pos = io_seek(fptr, pos, SEEK_SET);
    if (pos < 0 && errno) rb_sys_fail_path(fptr->pathv);

    return OFFT2NUM(pos);
}

Seeks to the given new_position (in bytes); see Position:

f = File.open('t.txt')
f.tell     # => 0
f.pos = 20 # => 20
f.tell     # => 20

Related: IO#seek, IO#tell.

ios.pread(maxlen, offset[, outbuf]) → string

io.c View on GitHub

          
            static VALUE
rb_io_pread(int argc, VALUE *argv, VALUE io)
{
    VALUE len, offset, str;
    rb_io_t *fptr;
    ssize_t n;
    struct prdwr_internal_arg arg;
    int shrinkable;

    rb_scan_args(argc, argv, "21", &len, &offset, &str);
    arg.count = NUM2SIZET(len);
    arg.offset = NUM2OFFT(offset);

    shrinkable = io_setstrbuf(&str, (long)arg.count);
    if (arg.count == 0) return str;
    arg.buf = RSTRING_PTR(str);

    GetOpenFile(io, fptr);
    rb_io_check_byte_readable(fptr);

    arg.fd = fptr->fd;
    rb_io_check_closed(fptr);

    rb_str_locktmp(str);
    n = (ssize_t)rb_ensure(pread_internal_call, (VALUE)&arg, rb_str_unlocktmp, str);

    if (n < 0) {
        rb_sys_fail_path(fptr->pathv);
    }
    io_set_read_length(str, n, shrinkable);
    if (n == 0 && arg.count > 0) {
        rb_eof_error();
    }

    return str;
}

Reads maxlen bytes from ios using the pread system call and returns them as a string without modifying the underlying descriptor offset. This is advantageous compared to combining IO#seek and IO#read in that it is atomic, allowing multiple threads/process to share the same IO object for reading the file at various locations. This bypasses any userspace buffering of the IO layer. If the optional outbuf argument is present, it must reference a String, which will receive the data. Raises SystemCallError on error, EOFError at end of file and NotImplementedError if platform does not implement the system call.

File.write("testfile", "This is line one\nThis is line two\n")
File.open("testfile") do |f|
  p f.read           # => "This is line one\nThis is line two\n"
  p f.pread(12, 0)   # => "This is line"
  p f.pread(9, 8)    # => "line one\n"
end

pressed?(p1)

ext/io/console/console.c View on GitHub

          
            static VALUE
console_key_pressed_p(VALUE io, VALUE k)
{
    int vk = -1;

    if (FIXNUM_P(k)) {
        vk = NUM2UINT(k);
    }
    else {
        const struct vktable *t;
        const char *kn;
        if (SYMBOL_P(k)) {
            k = rb_sym2str(k);
            kn = RSTRING_PTR(k);
        }
        else {
            kn = StringValuePtr(k);
        }
        t = console_win32_vk(kn, RSTRING_LEN(k));
        if (!t || (vk = (short)t->vk) == -1) {
            rb_raise(rb_eArgError, "unknown virtual key code: % "PRIsVALUE, k);
        }
    }
    return GetKeyState(vk) & 0x80 ? Qtrue : Qfalse;
}

No documentation available

ios.print → nil

ios.print(obj, ...) → nil

io.c View on GitHub

          
            VALUE
rb_io_print(int argc, const VALUE *argv, VALUE out)
{
    int i;
    VALUE line;

    /* if no argument given, print `$_' */
    if (argc == 0) {
        argc = 1;
        line = rb_lastline_get();
        argv = &line;
    }
    if (argc > 1 && !NIL_P(rb_output_fs)) {
        rb_category_warn(RB_WARN_CATEGORY_DEPRECATED, "$, is set to non-nil value");
    }
    for (i=0; i<argc; i++) {
        if (!NIL_P(rb_output_fs) && i>0) {
            rb_io_write(out, rb_output_fs);
        }
        rb_io_write(out, argv[i]);
    }
    if (argc > 0 && !NIL_P(rb_output_rs)) {
        rb_io_write(out, rb_output_rs);
    }

    return Qnil;
}

Writes the given object(s) to ios. Returns nil.

The stream must be opened for writing. Each given object that isn’t a string will be converted by calling its to_s method. When called without arguments, prints the contents of $_.

If the output field separator ($,) is not nil, it is inserted between objects. If the output record separator ($\) is not nil, it is appended to the output.

$stdout.print("This is ", 100, " percent.\n")

produces:

This is 100 percent.

ios.printf(format_string [, obj, ...]) → nil

io.c View on GitHub

          
            VALUE
rb_io_printf(int argc, const VALUE *argv, VALUE out)
{
    rb_io_write(out, rb_f_sprintf(argc, argv));
    return Qnil;
}

Formats and writes to ios, converting parameters under control of the format string. See Kernel#sprintf for details.

ios.putc(obj) → obj

io.c View on GitHub

          
            static VALUE
rb_io_putc(VALUE io, VALUE ch)
{
    VALUE str;
    if (RB_TYPE_P(ch, T_STRING)) {
        str = rb_str_substr(ch, 0, 1);
    }
    else {
        char c = NUM2CHR(ch);
        str = rb_str_new(&c, 1);
    }
    rb_io_write(io, str);
    return ch;
}

If obj is Numeric, write the character whose code is the least-significant byte of obj. If obj is String, write the first character of obj to ios. Otherwise, raise TypeError.

$stdout.putc "A"
$stdout.putc 65

produces:

AA

ios.puts(obj, ...) → nil

io.c View on GitHub

          
            VALUE
rb_io_puts(int argc, const VALUE *argv, VALUE out)
{
    int i, n;
    VALUE line, args[2];

    /* if no argument given, print newline. */
    if (argc == 0) {
        rb_io_write(out, rb_default_rs);
        return Qnil;
    }
    for (i=0; i<argc; i++) {
        if (RB_TYPE_P(argv[i], T_STRING)) {
            line = argv[i];
            goto string;
        }
        if (rb_exec_recursive(io_puts_ary, argv[i], out)) {
            continue;
        }
        line = rb_obj_as_string(argv[i]);
      string:
        n = 0;
        args[n++] = line;
        if (RSTRING_LEN(line) == 0 ||
            !rb_str_end_with_asciichar(line, '\n')) {
            args[n++] = rb_default_rs;
        }
        rb_io_writev(out, n, args);
    }

    return Qnil;
}

Writes the given object(s) to ios. Writes a newline after any that do not already end with a newline sequence. Returns nil.

The stream must be opened for writing. If called with an array argument, writes each element on a new line. Each given object that isn’t a string or array will be converted by calling its to_s method. If called without arguments, outputs a single newline.

$stdout.puts("this", "is", ["a", "test"])

produces:

this
is
a
test

Note that puts always uses newlines and is not affected by the output record separator ($\).

ios.pwrite(string, offset) → integer

io.c View on GitHub

          
            static VALUE
rb_io_pwrite(VALUE io, VALUE str, VALUE offset)
{
    rb_io_t *fptr;
    ssize_t n;
    struct prdwr_internal_arg arg;
    VALUE tmp;

    if (!RB_TYPE_P(str, T_STRING))
        str = rb_obj_as_string(str);

    arg.offset = NUM2OFFT(offset);

    io = GetWriteIO(io);
    GetOpenFile(io, fptr);
    rb_io_check_writable(fptr);
    arg.fd = fptr->fd;

    tmp = rb_str_tmp_frozen_acquire(str);
    arg.buf = RSTRING_PTR(tmp);
    arg.count = (size_t)RSTRING_LEN(tmp);

    n = (ssize_t)rb_thread_io_blocking_region(internal_pwrite_func, &arg, fptr->fd);
    if (n < 0) rb_sys_fail_path(fptr->pathv);
    rb_str_tmp_frozen_release(str, tmp);

    return SSIZET2NUM(n);
}

Writes the given string to ios at offset using pwrite() system call. This is advantageous to combining IO#seek and IO#write in that it is atomic, allowing multiple threads/process to share the same IO object for reading the file at various locations. This bypasses any userspace buffering of the IO layer. Returns the number of bytes written. Raises SystemCallError on error and NotImplementedError if platform does not implement the system call.

File.open("out", "w") do |f|
  f.pwrite("ABCDEF", 3)   #=> 6
end

File.read("out")          #=> "\u0000\u0000\u0000ABCDEF"

io.raw(min: nil, time: nil, intr: nil) {|io| }

ext/io/console/console.c View on GitHub

          
            static VALUE
console_raw(int argc, VALUE *argv, VALUE io)
{
    rawmode_arg_t opts, *optp = rawmode_opt(&argc, argv, 0, 0, &opts);
    return ttymode(io, rb_yield, io, set_rawmode, optp);
}

Yields self within raw mode, and returns the result of the block.

STDIN.raw(&:gets)

will read and return a line without echo back and line editing.

The parameter min specifies the minimum number of bytes that should be received when a read operation is performed. (default: 1)

The parameter time specifies the timeout in seconds with a precision of 1/10 of a second. (default: 0)

If the parameter intr is true, enables break, interrupt, quit, and suspend special characters.

Refer to the manual page of termios for further details.

You must require ‘io/console’ to use this method.

io.raw!(min: nil, time: nil, intr: nil) → io

ext/io/console/console.c View on GitHub

          
            static VALUE
console_set_raw(int argc, VALUE *argv, VALUE io)
{
    conmode t;
    rb_io_t *fptr;
    int fd;
    rawmode_arg_t opts, *optp = rawmode_opt(&argc, argv, 0, 0, &opts);

    GetOpenFile(io, fptr);
    fd = GetReadFD(fptr);
    if (!getattr(fd, &t)) sys_fail_fptr(fptr);
    set_rawmode(&t, optp);
    if (!setattr(fd, &t)) sys_fail_fptr(fptr);
    return io;
}

Enables raw mode, and returns io.

If the terminal mode needs to be back, use io.raw { ... }.

See IO#raw for details on the parameters.

You must require ‘io/console’ to use this method.

read(maxlen = nil) → string or nil

read(maxlen = nil, out_string) → out_string or nil

io.c View on GitHub

          
            static VALUE
io_read(int argc, VALUE *argv, VALUE io)
{
    rb_io_t *fptr;
    long n, len;
    VALUE length, str;
    int shrinkable;
#if RUBY_CRLF_ENVIRONMENT
    int previous_mode;
#endif

    rb_scan_args(argc, argv, "02", &length, &str);

    if (NIL_P(length)) {
        GetOpenFile(io, fptr);
        rb_io_check_char_readable(fptr);
        return read_all(fptr, remain_size(fptr), str);
    }
    len = NUM2LONG(length);
    if (len < 0) {
        rb_raise(rb_eArgError, "negative length %ld given", len);
    }

    shrinkable = io_setstrbuf(&str,len);

    GetOpenFile(io, fptr);
    rb_io_check_byte_readable(fptr);
    if (len == 0) {
        io_set_read_length(str, 0, shrinkable);
        return str;
    }

    READ_CHECK(fptr);
#if RUBY_CRLF_ENVIRONMENT
    previous_mode = set_binary_mode_with_seek_cur(fptr);
#endif
    n = io_fread(str, 0, len, fptr);
    io_set_read_length(str, n, shrinkable);
#if RUBY_CRLF_ENVIRONMENT
    if (previous_mode == O_TEXT) {
        setmode(fptr->fd, O_TEXT);
    }
#endif
    if (n == 0) return Qnil;

    return str;
}

Reads bytes from the stream (in binary mode):

If maxlen is nil, reads all bytes.
Otherwise reads maxlen bytes, if available.
Otherwise reads all bytes.

Returns a string (either a new string or the given out_string) containing the bytes read. The encoding of the string depends on both maxLen and out_string:

maxlen is nil: uses internal encoding of self (regardless of whether out_string was given).
maxlen not nil:
- out_string given: encoding of out_string not modified.
- out_string not given: ASCII-8BIT is used.

Without Argument out_string

When argument out_string is omitted, the returned value is a new string:

f = File.new('t.txt')
f.read
# => "This is line one.\nThis is the second line.\nThis is the third line.\n"
f.rewind
f.read(40)      # => "This is line one.\r\nThis is the second li"
f.read(40)      # => "ne.\r\nThis is the third line.\r\n"
f.read(40)      # => nil

If maxlen is zero, returns an empty string.

With Argument out_string

When argument out_string is given, the returned value is out_string, whose content is replaced:

f = File.new('t.txt')
s = 'foo'      # => "foo"
f.read(nil, s) # => "This is line one.\nThis is the second line.\nThis is the third line.\n"
s              # => "This is line one.\nThis is the second line.\nThis is the third line.\n"
f.rewind
s = 'bar'
f.read(40, s)  # => "This is line one.\r\nThis is the second li"
s              # => "This is line one.\r\nThis is the second li"
s = 'baz'
f.read(40, s)  # => "ne.\r\nThis is the third line.\r\n"
s              # => "ne.\r\nThis is the third line.\r\n"
s = 'bat'
f.read(40, s)  # => nil
s              # => ""

Note that this method behaves like the fread() function in C. This means it retries to invoke read(2) system calls to read data with the specified maxlen (or until EOF).

This behavior is preserved even if the stream is in non-blocking mode. (This method is non-blocking-flag insensitive as other methods.)

If you need the behavior like a single read(2) system call, consider readpartial, read_nonblock, and sysread.

ios.read_nonblock(maxlen [, options]) → string

ios.read_nonblock(maxlen, outbuf [, options]) → outbuf

io.rb View on GitHub

          
            # File tmp/rubies/ruby-3.1.3/io.rb, line 62
def read_nonblock(len, buf = nil, exception: true)
  Primitive.io_read_nonblock(len, buf, exception)
end

Reads at most maxlen bytes from ios using the read(2) system call after O_NONBLOCK is set for the underlying file descriptor.

If the optional outbuf argument is present, it must reference a String, which will receive the data. The outbuf will contain only the received data after the method call even if it is not empty at the beginning.

read_nonblock just calls the read(2) system call. It causes all errors the read(2) system call causes: Errno::EWOULDBLOCK, Errno::EINTR, etc. The caller should care such errors.

If the exception is Errno::EWOULDBLOCK or Errno::EAGAIN, it is extended by IO::WaitReadable. So IO::WaitReadable can be used to rescue the exceptions for retrying read_nonblock.

read_nonblock causes EOFError on EOF.

On some platforms, such as Windows, non-blocking mode is not supported on IO objects other than sockets. In such cases, Errno::EBADF will be raised.

If the read byte buffer is not empty, read_nonblock reads from the buffer like readpartial. In this case, the read(2) system call is not called.

When read_nonblock raises an exception kind of IO::WaitReadable, read_nonblock should not be called until io is readable for avoiding busy loop. This can be done as follows.

# emulates blocking read (readpartial).
begin
  result = io.read_nonblock(maxlen)
rescue IO::WaitReadable
  IO.select([io])
  retry
end

Although IO#read_nonblock doesn’t raise IO::WaitWritable. OpenSSL::Buffering#read_nonblock can raise IO::WaitWritable. If IO and SSL should be used polymorphically, IO::WaitWritable should be rescued too. See the document of OpenSSL::Buffering#read_nonblock for sample code.

Note that this method is identical to readpartial except the non-blocking flag is set.

By specifying a keyword argument exception to false, you can indicate that read_nonblock should not raise an IO::WaitReadable exception, but return the symbol :wait_readable instead. At EOF, it will return nil instead of raising EOFError.

ios.readbyte → integer

io.c View on GitHub

          
            static VALUE
rb_io_readbyte(VALUE io)
{
    VALUE c = rb_io_getbyte(io);

    if (NIL_P(c)) {
        rb_eof_error();
    }
    return c;
}

Reads a byte as with IO#getbyte, but raises an EOFError on end of file.

ios.readchar → string

io.c View on GitHub

          
            static VALUE
rb_io_readchar(VALUE io)
{
    VALUE c = rb_io_getc(io);

    if (NIL_P(c)) {
        rb_eof_error();
    }
    return c;
}

Reads a one-character string from ios. Raises an EOFError on end of file.

f = File.new("testfile")
f.readchar   #=> "h"
f.readchar   #=> "e"

ios.readline(sep=$/ [, getline_args]) → string

ios.readline(limit [, getline_args]) → string

ios.readline(sep, limit [, getline_args]) → string

io.c View on GitHub

          
            static VALUE
rb_io_readline(int argc, VALUE *argv, VALUE io)
{
    VALUE line = rb_io_gets_m(argc, argv, io);

    if (NIL_P(line)) {
        rb_eof_error();
    }
    return line;
}

Reads a line as with IO#gets, but raises an EOFError on end of file.

ios.readlines(sep=$/ [, getline_args]) → array

ios.readlines(limit [, getline_args]) → array

ios.readlines(sep, limit [, getline_args]) → array

io.c View on GitHub

          
            static VALUE
rb_io_readlines(int argc, VALUE *argv, VALUE io)
{
    struct getline_arg args;

    prepare_getline_args(argc, argv, &args, io);
    return io_readlines(&args, io);
}

Reads all of the lines in ios, and returns them in an array. Lines are separated by the optional sep. If sep is nil, the rest of the stream is returned as a single record. If the first argument is an integer, or an optional second argument is given, the returning string would not be longer than the given value in bytes. The stream must be opened for reading or an IOError will be raised.

f = File.new("testfile")
f.readlines[0]   #=> "This is line one\n"

f = File.new("testfile", chomp: true)
f.readlines[0]   #=> "This is line one"

See IO.readlines for details about getline_args.

readpartial(maxlen) → string

readpartial(maxlen, out_string) → out_string

io.c View on GitHub

          
            static VALUE
io_readpartial(int argc, VALUE *argv, VALUE io)
{
    VALUE ret;

    ret = io_getpartial(argc, argv, io, Qnil, 0);
    if (NIL_P(ret))
        rb_eof_error();
    return ret;
}

Reads up to maxlen bytes from the stream; returns a string (either a new string or the given out_string). Its encoding is:

The unchanged encoding of out_string, if out_string is given.
ASCII-8BIT, otherwise.
Contains maxlen bytes from the stream, if available.
Otherwise contains all available bytes, if any available.
Otherwise is an empty string.

With the single non-negative integer argument maxlen given, returns a new string:

f = File.new('t.txt')
f.readpartial(30) # => "This is line one.\nThis is the"
f.readpartial(30) # => " second line.\nThis is the thi"
f.readpartial(30) # => "rd line.\n"
f.eof             # => true
f.readpartial(30) # Raises EOFError.

With both argument maxlen and string argument out_string given, returns modified out_string:

f = File.new('t.txt')
s = 'foo'
f.readpartial(30, s) # => "This is line one.\nThis is the"
s = 'bar'
f.readpartial(0, s)  # => ""

This method is useful for a stream such as a pipe, a socket, or a tty. It blocks only when no data is immediately available. This means that it blocks only when all of the following are true:

The byte buffer in the stream is empty.
The content of the stream is empty.
The stream is not at EOF.

When blocked, the method waits for either more data or EOF on the stream:

If more data is read, the method returns the data.
If EOF is reached, the method raises EOFError.

When not blocked, the method responds immediately:

Returns data from the buffer if there is any.
Otherwise returns data from the stream if there is any.
Otherwise raises EOFError if the stream has reached EOF.

Note that this method is similar to sysread. The differences are:

If the byte buffer is not empty, read from the byte buffer instead of “sysread for buffered IO (IOError)”.
It doesn’t cause Errno::EWOULDBLOCK and Errno::EINTR. When readpartial meets EWOULDBLOCK and EINTR by read system call, readpartial retries the system call.

The latter means that readpartial is non-blocking-flag insensitive. It blocks on the situation IO#sysread causes Errno::EWOULDBLOCK as if the fd is blocking mode.

Examples:

#                        # Returned      Buffer Content    Pipe Content
r, w = IO.pipe           #
w << 'abc'               #               ""                "abc".
r.readpartial(4096)      # => "abc"      ""                ""
r.readpartial(4096)      # (Blocks because buffer and pipe are empty.)

#                        # Returned      Buffer Content    Pipe Content
r, w = IO.pipe           #
w << 'abc'               #               ""                "abc"
w.close                  #               ""                "abc" EOF
r.readpartial(4096)      # => "abc"      ""                 EOF
r.readpartial(4096)      # raises EOFError

#                        # Returned      Buffer Content    Pipe Content
r, w = IO.pipe           #
w << "abc\ndef\n"        #               ""                "abc\ndef\n"
r.gets                   # => "abc\n"    "def\n"           ""
w << "ghi\n"             #               "def\n"           "ghi\n"
r.readpartial(4096)      # => "def\n"    ""                "ghi\n"
r.readpartial(4096)      # => "ghi\n"    ""                ""

io.ready? → true or false

ext/io/wait/wait.c View on GitHub

          
            static VALUE
io_ready_p(VALUE io)
{
    rb_io_t *fptr;
#ifndef HAVE_RB_IO_WAIT
    struct timeval tv = {0, 0};
#endif

    GetOpenFile(io, fptr);
    rb_io_check_readable(fptr);
    if (rb_io_read_pending(fptr)) return Qtrue;

#ifndef HAVE_RB_IO_WAIT
    if (wait_for_single_fd(fptr, RB_WAITFD_IN, &tv))
        return Qtrue;
#else
    if (RTEST(io_wait_event(io, RUBY_IO_READABLE, RB_INT2NUM(0))))
        return Qtrue;
#endif
    return Qfalse;
}

Returns true if input available without blocking, or false.

ios.reopen(other_IO) → ios

ios.reopen(path, mode [, opt]) → ios

io.c View on GitHub

          
            static VALUE
rb_io_reopen(int argc, VALUE *argv, VALUE file)
{
    VALUE fname, nmode, opt;
    int oflags;
    rb_io_t *fptr;

    if (rb_scan_args(argc, argv, "11:", &fname, &nmode, &opt) == 1) {
        VALUE tmp = rb_io_check_io(fname);
        if (!NIL_P(tmp)) {
            return io_reopen(file, tmp);
        }
    }

    FilePathValue(fname);
    rb_io_taint_check(file);
    fptr = RFILE(file)->fptr;
    if (!fptr) {
        fptr = RFILE(file)->fptr = ZALLOC(rb_io_t);
    }

    if (!NIL_P(nmode) || !NIL_P(opt)) {
        int fmode;
        convconfig_t convconfig;

        rb_io_extract_modeenc(&nmode, 0, opt, &oflags, &fmode, &convconfig);
        if (IS_PREP_STDIO(fptr) &&
            ((fptr->mode & FMODE_READWRITE) & (fmode & FMODE_READWRITE)) !=
            (fptr->mode & FMODE_READWRITE)) {
            rb_raise(rb_eArgError,
                     "%s can't change access mode from \"%s\" to \"%s\"",
                     PREP_STDIO_NAME(fptr), rb_io_fmode_modestr(fptr->mode),
                     rb_io_fmode_modestr(fmode));
        }
        fptr->mode = fmode;
        fptr->encs = convconfig;
    }
    else {
        oflags = rb_io_fmode_oflags(fptr->mode);
    }

    fptr->pathv = fname;
    if (fptr->fd < 0) {
        fptr->fd = rb_sysopen(fptr->pathv, oflags, 0666);
        fptr->stdio_file = 0;
        return file;
    }

    if (fptr->mode & FMODE_WRITABLE) {
        if (io_fflush(fptr) < 0)
            rb_sys_fail_on_write(fptr);
    }
    fptr->rbuf.off = fptr->rbuf.len = 0;

    if (fptr->stdio_file) {
        int e = rb_freopen(rb_str_encode_ospath(fptr->pathv),
                           rb_io_oflags_modestr(oflags),
                           fptr->stdio_file);
        if (e) rb_syserr_fail_path(e, fptr->pathv);
        fptr->fd = fileno(fptr->stdio_file);
        rb_fd_fix_cloexec(fptr->fd);
#ifdef USE_SETVBUF
        if (setvbuf(fptr->stdio_file, NULL, _IOFBF, 0) != 0)
            rb_warn("setvbuf() can't be honoured for %"PRIsVALUE, fptr->pathv);
#endif
        if (fptr->stdio_file == stderr) {
            if (setvbuf(fptr->stdio_file, NULL, _IONBF, BUFSIZ) != 0)
                rb_warn("setvbuf() can't be honoured for %"PRIsVALUE, fptr->pathv);
        }
        else if (fptr->stdio_file == stdout && isatty(fptr->fd)) {
            if (setvbuf(fptr->stdio_file, NULL, _IOLBF, BUFSIZ) != 0)
                rb_warn("setvbuf() can't be honoured for %"PRIsVALUE, fptr->pathv);
        }
    }
    else {
        int tmpfd = rb_sysopen(fptr->pathv, oflags, 0666);
        int err = 0;
        if (rb_cloexec_dup2(tmpfd, fptr->fd) < 0)
            err = errno;
        (void)close(tmpfd);
        if (err) {
            rb_syserr_fail_path(err, fptr->pathv);
        }
    }

    return file;
}

Reassociates ios with the I/O stream given in other_IO or to a new stream opened on path. This may dynamically change the actual class of this stream. The mode and opt parameters accept the same values as IO.open.

f1 = File.new("testfile")
f2 = File.new("testfile")
f2.readlines[0]   #=> "This is line one\n"
f2.reopen(f1)     #=> #<File:testfile>
f2.readlines[0]   #=> "This is line one\n"

rewind → 0

io.c View on GitHub

          
            static VALUE
rb_io_rewind(VALUE io)
{
    rb_io_t *fptr;

    GetOpenFile(io, fptr);
    if (io_seek(fptr, 0L, 0) < 0 && errno) rb_sys_fail_path(fptr->pathv);
    if (io == ARGF.current_file) {
        ARGF.lineno -= fptr->lineno;
    }
    fptr->lineno = 0;
    if (fptr->readconv) {
        clear_readconv(fptr);
    }

    return INT2FIX(0);
}

Repositions the stream to its beginning, setting both the position and the line number to zero; see Position and Line Number:

f = File.open('t.txt')
f.tell     # => 0
f.lineno   # => 0
f.readline # => "This is line one.\n"
f.tell     # => 19
f.lineno   # => 1
f.rewind   # => 0
f.tell     # => 0
f.lineno   # => 0

Note that this method cannot be used with streams such as pipes, ttys, and sockets.

scroll_backward(p1)

ext/io/console/console.c View on GitHub

          
            static VALUE
console_scroll_backward(VALUE io, VALUE val)
{
    return console_scroll(io, -NUM2INT(val));
}

No documentation available

scroll_forward(p1)

ext/io/console/console.c View on GitHub

          
            static VALUE
console_scroll_forward(VALUE io, VALUE val)
{
    return console_scroll(io, +NUM2INT(val));
}

No documentation available

seek(offset, whence = IO::SEEK_SET) → 0

io.c View on GitHub

          
            static VALUE
rb_io_seek_m(int argc, VALUE *argv, VALUE io)
{
    VALUE offset, ptrname;
    int whence = SEEK_SET;

    if (rb_scan_args(argc, argv, "11", &offset, &ptrname) == 2) {
        whence = interpret_seek_whence(ptrname);
    }

    return rb_io_seek(io, offset, whence);
}

Seeks to the position given by integer offset (see Position) and constant whence, which is one of:

:CUR or IO::SEEK_CUR: Repositions the stream to its current position plus the given offset:

f = File.open('t.txt')
f.tell            # => 0
f.seek(20, :CUR)  # => 0
f.tell            # => 20
f.seek(-10, :CUR) # => 0
f.tell            # => 10

:END or IO::SEEK_END: Repositions the stream to its end plus the given offset:

f = File.open('t.txt')
f.tell            # => 0
f.seek(0, :END)   # => 0  # Repositions to stream end.
f.tell            # => 70
f.seek(-20, :END) # => 0
f.tell            # => 50
f.seek(-40, :END) # => 0
f.tell            # => 30

:SET or IO:SEEK_SET: Repositions the stream to the given offset:

f = File.open('t.txt')
f.tell            # => 0
f.seek(20, :SET) # => 0
f.tell           # => 20
f.seek(40, :SET) # => 0
f.tell           # => 40

Related: IO#pos=, IO#tell.

io.set_encoding(ext_enc) → io

io.set_encoding("ext_enc:int_enc") → io

io.set_encoding(ext_enc, int_enc) → io

io.set_encoding("ext_enc:int_enc", opt) → io

io.set_encoding(ext_enc, int_enc, opt) → io

io.c View on GitHub

          
            static VALUE
rb_io_set_encoding(int argc, VALUE *argv, VALUE io)
{
    rb_io_t *fptr;
    VALUE v1, v2, opt;

    if (!RB_TYPE_P(io, T_FILE)) {
        return forward(io, id_set_encoding, argc, argv);
    }

    argc = rb_scan_args(argc, argv, "11:", &v1, &v2, &opt);
    GetOpenFile(io, fptr);
    io_encoding_set(fptr, v1, v2, opt);
    return io;
}

If single argument is specified, read string from io is tagged with the encoding specified. If encoding is a colon separated two encoding names “A:B”, the read string is converted from encoding A (external encoding) to encoding B (internal encoding), then tagged with B. If two arguments are specified, those must be encoding objects or encoding names, and the first one is the external encoding, and the second one is the internal encoding. If the external encoding and the internal encoding is specified, optional hash argument specify the conversion option.

ios.set_encoding_by_bom → encoding or nil

io.c View on GitHub

          
            static VALUE
rb_io_set_encoding_by_bom(VALUE io)
{
    rb_io_t *fptr;

    GetOpenFile(io, fptr);
    if (!(fptr->mode & FMODE_BINMODE)) {
        rb_raise(rb_eArgError, "ASCII incompatible encoding needs binmode");
    }
    if (fptr->encs.enc2) {
        rb_raise(rb_eArgError, "encoding conversion is set");
    }
    else if (fptr->encs.enc && fptr->encs.enc != rb_ascii8bit_encoding()) {
        rb_raise(rb_eArgError, "encoding is set to %s already",
                 rb_enc_name(fptr->encs.enc));
    }
    if (!io_set_encoding_by_bom(io)) return Qnil;
    return rb_enc_from_encoding(fptr->encs.enc);
}

Checks if ios starts with a BOM, and then consumes it and sets the external encoding. Returns the result encoding if found, or nil. If ios is not binmode or its encoding has been set already, an exception will be raised.

File.write("bom.txt", "\u{FEFF}abc")
ios = File.open("bom.txt", "rb")
ios.set_encoding_by_bom    #=>  #<Encoding:UTF-8>

File.write("nobom.txt", "abc")
ios = File.open("nobom.txt", "rb")
ios.set_encoding_by_bom    #=>  nil

ios.stat → stat

file.c View on GitHub

          
            static VALUE
rb_io_stat(VALUE obj)
{
    rb_io_t *fptr;
    struct stat st;

    GetOpenFile(obj, fptr);
    if (fstat(fptr->fd, &st) == -1) {
        rb_sys_fail_path(fptr->pathv);
    }
    return rb_stat_new(&st);
}

Returns status information for ios as an object of type File::Stat.

f = File.new("testfile")
s = f.stat
"%o" % s.mode   #=> "100644"
s.blksize       #=> 4096
s.atime         #=> Wed Apr 09 08:53:54 CDT 2003

sync → true or false

io.c View on GitHub

          
            static VALUE
rb_io_sync(VALUE io)
{
    rb_io_t *fptr;

    io = GetWriteIO(io);
    GetOpenFile(io, fptr);
    return RBOOL(fptr->mode & FMODE_SYNC);
}

Returns the current sync mode of the stream. When sync mode is true, all output is immediately flushed to the underlying operating system and is not buffered by Ruby internally. See also fsync.

f = File.open('t.tmp', 'w')
f.sync # => false
f.sync = true
f.sync # => true

sync = boolean → boolean

io.c View on GitHub

          
            static VALUE
rb_io_set_sync(VALUE io, VALUE sync)
{
    rb_io_t *fptr;

    io = GetWriteIO(io);
    GetOpenFile(io, fptr);
    if (RTEST(sync)) {
        fptr->mode |= FMODE_SYNC;
    }
    else {
        fptr->mode &= ~FMODE_SYNC;
    }
    return sync;
}

Sets the sync mode for the stream to the given value; returns the given value.

Values for the sync mode:

true: All output is immediately flushed to the underlying operating system and is not buffered internally.
false: Output may be buffered internally.

Example;

f = File.open('t.tmp', 'w')
f.sync # => false
f.sync = true
f.sync # => true

Related: IO#fsync.

ios.sysread(maxlen[, outbuf]) → string

io.c View on GitHub

          
            static VALUE
rb_io_sysread(int argc, VALUE *argv, VALUE io)
{
    VALUE len, str;
    rb_io_t *fptr;
    long n, ilen;
    struct io_internal_read_struct iis;
    int shrinkable;

    rb_scan_args(argc, argv, "11", &len, &str);
    ilen = NUM2LONG(len);

    shrinkable = io_setstrbuf(&str, ilen);
    if (ilen == 0) return str;

    GetOpenFile(io, fptr);
    rb_io_check_byte_readable(fptr);

    if (READ_DATA_BUFFERED(fptr)) {
        rb_raise(rb_eIOError, "sysread for buffered IO");
    }

    rb_io_check_closed(fptr);

    io_setstrbuf(&str, ilen);
    iis.th = rb_thread_current();
    iis.fptr = fptr;
    iis.nonblock = 0;
    iis.buf = RSTRING_PTR(str);
    iis.capa = ilen;
    n = read_internal_locktmp(str, &iis);

    if (n < 0) {
        rb_sys_fail_path(fptr->pathv);
    }

    io_set_read_length(str, n, shrinkable);

    if (n == 0 && ilen > 0) {
        rb_eof_error();
    }

    return str;
}

Reads maxlen bytes from ios using a low-level read and returns them as a string. Do not mix with other methods that read from ios or you may get unpredictable results.

Raises SystemCallError on error and EOFError at end of file.

f = File.new("testfile")
f.sysread(16)   #=> "This is line one"

ios.sysseek(offset, whence=IO::SEEK_SET) → integer

io.c View on GitHub

          
            static VALUE
rb_io_sysseek(int argc, VALUE *argv, VALUE io)
{
    VALUE offset, ptrname;
    int whence = SEEK_SET;
    rb_io_t *fptr;
    off_t pos;

    if (rb_scan_args(argc, argv, "11", &offset, &ptrname) == 2) {
        whence = interpret_seek_whence(ptrname);
    }
    pos = NUM2OFFT(offset);
    GetOpenFile(io, fptr);
    if ((fptr->mode & FMODE_READABLE) &&
        (READ_DATA_BUFFERED(fptr) || READ_CHAR_PENDING(fptr))) {
        rb_raise(rb_eIOError, "sysseek for buffered IO");
    }
    if ((fptr->mode & FMODE_WRITABLE) && fptr->wbuf.len) {
        rb_warn("sysseek for buffered IO");
    }
    errno = 0;
    pos = lseek(fptr->fd, pos, whence);
    if (pos < 0 && errno) rb_sys_fail_path(fptr->pathv);

    return OFFT2NUM(pos);
}

Seeks to a given offset in the stream according to the value of whence (see IO#seek for values of whence). Returns the new offset into the file.

f = File.new("testfile")
f.sysseek(-13, IO::SEEK_END)   #=> 53
f.sysread(10)                  #=> "And so on."

ios.syswrite(string) → integer

io.c View on GitHub

          
            static VALUE
rb_io_syswrite(VALUE io, VALUE str)
{
    VALUE tmp;
    rb_io_t *fptr;
    long n, len;
    const char *ptr;

    if (!RB_TYPE_P(str, T_STRING))
        str = rb_obj_as_string(str);

    io = GetWriteIO(io);
    GetOpenFile(io, fptr);
    rb_io_check_writable(fptr);

    if (fptr->wbuf.len) {
        rb_warn("syswrite for buffered IO");
    }

    tmp = rb_str_tmp_frozen_acquire(str);
    RSTRING_GETMEM(tmp, ptr, len);
    n = rb_write_internal(fptr, ptr, len);
    if (n < 0) rb_sys_fail_path(fptr->pathv);
    rb_str_tmp_frozen_release(str, tmp);

    return LONG2FIX(n);
}

Writes the given string to ios using a low-level write. Returns the number of bytes written. Do not mix with other methods that write to ios or you may get unpredictable results. Raises SystemCallError on error.

f = File.new("out", "w")
f.syswrite("ABCDEF")   #=> 6

tell → integer

io.c View on GitHub

          
            static VALUE
rb_io_tell(VALUE io)
{
    rb_io_t *fptr;
    off_t pos;

    GetOpenFile(io, fptr);
    pos = io_tell(fptr);
    if (pos < 0 && errno) rb_sys_fail_path(fptr->pathv);
    pos -= fptr->rbuf.len;
    return OFFT2NUM(pos);
}

Returns the current position (in bytes) in self (see Position):

f = File.new('t.txt')
f.tell     # => 0
f.readline # => "This is line one.\n"
f.tell     # => 19

Related: IO#pos=, IO#seek.

IO#pos is an alias for IO#tell.

to_i

io.c View on GitHub

An alias for fileno

to_io → self

io.c View on GitHub

          
            static VALUE
rb_io_to_io(VALUE io)
{
    return io;
}

Returns self.

ios.tty? → true or false

io.c View on GitHub

An alias for isatty

ios.ungetbyte(string) → nil

ios.ungetbyte(integer) → nil

io.c View on GitHub

          
            VALUE
rb_io_ungetbyte(VALUE io, VALUE b)
{
    rb_io_t *fptr;

    GetOpenFile(io, fptr);
    rb_io_check_byte_readable(fptr);
    switch (TYPE(b)) {
      case T_NIL:
        return Qnil;
      case T_FIXNUM:
      case T_BIGNUM: ;
        VALUE v = rb_int_modulo(b, INT2FIX(256));
        unsigned char c = NUM2INT(v) & 0xFF;
        b = rb_str_new((const char *)&c, 1);
        break;
      default:
        SafeStringValue(b);
    }
    io_ungetbyte(b, fptr);
    return Qnil;
}

Pushes back bytes (passed as a parameter) onto ios, such that a subsequent buffered read will return it. It is only guaranteed to support a single byte, and only if ungetbyte or ungetc has not already been called on ios since the previous read of at least a single byte from ios. However, it can support additional bytes if there is space in the internal buffer to allow for it.

f = File.new("testfile")   #=> #<File:testfile>
b = f.getbyte              #=> 0x38
f.ungetbyte(b)             #=> nil
f.getbyte                  #=> 0x38

If given an integer, only uses the lower 8 bits of the integer as the byte to push.

f = File.new("testfile")   #=> #<File:testfile>
f.ungetbyte(0x102)         #=> nil
f.getbyte                  #=> 0x2

Calling this method prepends to the existing buffer, even if the method has already been called previously:

f = File.new("testfile")   #=> #<File:testfile>
f.ungetbyte("ab")          #=> nil
f.ungetbyte("cd")          #=> nil
f.read(5)                  #=> "cdab8"

Has no effect with unbuffered reads (such as IO#sysread).

ios.ungetc(integer) → nil

ios.ungetc(string) → nil

io.c View on GitHub

          
            VALUE
rb_io_ungetc(VALUE io, VALUE c)
{
    rb_io_t *fptr;
    long len;

    GetOpenFile(io, fptr);
    rb_io_check_char_readable(fptr);
    if (FIXNUM_P(c)) {
        c = rb_enc_uint_chr(FIX2UINT(c), io_read_encoding(fptr));
    }
    else if (RB_BIGNUM_TYPE_P(c)) {
        c = rb_enc_uint_chr(NUM2UINT(c), io_read_encoding(fptr));
    }
    else {
        SafeStringValue(c);
    }
    if (NEED_READCONV(fptr)) {
        SET_BINARY_MODE(fptr);
        len = RSTRING_LEN(c);
#if SIZEOF_LONG > SIZEOF_INT
        if (len > INT_MAX)
            rb_raise(rb_eIOError, "ungetc failed");
#endif
        make_readconv(fptr, (int)len);
        if (fptr->cbuf.capa - fptr->cbuf.len < len)
            rb_raise(rb_eIOError, "ungetc failed");
        if (fptr->cbuf.off < len) {
            MEMMOVE(fptr->cbuf.ptr+fptr->cbuf.capa-fptr->cbuf.len,
                    fptr->cbuf.ptr+fptr->cbuf.off,
                    char, fptr->cbuf.len);
            fptr->cbuf.off = fptr->cbuf.capa-fptr->cbuf.len;
        }
        fptr->cbuf.off -= (int)len;
        fptr->cbuf.len += (int)len;
        MEMMOVE(fptr->cbuf.ptr+fptr->cbuf.off, RSTRING_PTR(c), char, len);
    }
    else {
        NEED_NEWLINE_DECORATOR_ON_READ_CHECK(fptr);
        io_ungetbyte(c, fptr);
    }
    return Qnil;
}

Pushes back characters (passed as a parameter) onto ios, such that a subsequent buffered read will return it. It is only guaranteed to support a single byte, and only if ungetbyte or ungetc has not already been called on ios since the previous read of at least a single byte from ios. However, it can support additional bytes if there is space in the internal buffer to allow for it.

f = File.new("testfile")   #=> #<File:testfile>
c = f.getc                 #=> "8"
f.ungetc(c)                #=> nil
f.getc                     #=> "8"

If given an integer, the integer must represent a valid codepoint in the external encoding of ios.

Calling this method prepends to the existing buffer, even if the method has already been called previously:

f = File.new("testfile")   #=> #<File:testfile>
f.ungetc("ab")             #=> nil
f.ungetc("cd")             #=> nil
f.read(5)                  #=> "cdab8"

Has no effect with unbuffered reads (such as IO#sysread).

io.wait(events, timeout) → event mask or false.

io.wait(timeout = nil, mode = :read) → event mask or false.

ext/io/wait/wait.c View on GitHub

          
            static VALUE
io_wait(int argc, VALUE *argv, VALUE io)
{
#ifndef HAVE_RB_IO_WAIT
    rb_io_t *fptr;
    struct timeval timerec;
    struct timeval *tv = NULL;
    int event = 0;
    int i;

    GetOpenFile(io, fptr);
    for (i = 0; i < argc; ++i) {
        if (SYMBOL_P(argv[i])) {
            event |= wait_mode_sym(argv[i]);
        }
        else {
            *(tv = &timerec) = rb_time_interval(argv[i]);
        }
    }
    /* rb_time_interval() and might_mode() might convert the argument */
    rb_io_check_closed(fptr);
    if (!event) event = RB_WAITFD_IN;
    if ((event & RB_WAITFD_IN) && rb_io_read_pending(fptr))
        return Qtrue;
    if (wait_for_single_fd(fptr, event, tv))
        return io;
    return Qnil;
#else
    VALUE timeout = Qundef;
    rb_io_event_t events = 0;

    if (argc != 2 || (RB_SYMBOL_P(argv[0]) || RB_SYMBOL_P(argv[1]))) {
        for (int i = 0; i < argc; i += 1) {
            if (RB_SYMBOL_P(argv[i])) {
                events |= wait_mode_sym(argv[i]);
            }
            else if (timeout == Qundef) {
                rb_time_interval(timeout = argv[i]);
            }
            else {
                rb_raise(rb_eArgError, "timeout given more than once");
            }
        }
        if (timeout == Qundef) timeout = Qnil;
    }
    else /* argc == 2 */ {
        events = RB_NUM2UINT(argv[0]);
        timeout = argv[1];
    }

    if (events == 0) {
        events = RUBY_IO_READABLE;
    }

    if (events & RUBY_IO_READABLE) {
        rb_io_t *fptr = NULL;
        RB_IO_POINTER(io, fptr);

        if (rb_io_read_pending(fptr)) {
            return Qtrue;
        }
    }

    return io_wait_event(io, events, timeout);
#endif
}

Waits until the IO becomes ready for the specified events and returns the subset of events that become ready, or false when times out.

The events can be a bit mask of IO::READABLE, IO::WRITABLE or IO::PRIORITY.

Returns true immediately when buffered data is available.

Optional parameter mode is one of :read, :write, or :read_write.

io.wait_priority → true or false

io.wait_priority(timeout) → true or false

ext/io/wait/wait.c View on GitHub

          
            static VALUE
io_wait_priority(int argc, VALUE *argv, VALUE io)
{
    rb_io_t *fptr = NULL;

    RB_IO_POINTER(io, fptr);
    rb_io_check_readable(fptr);

    if (rb_io_read_pending(fptr)) return Qtrue;

    rb_check_arity(argc, 0, 1);
    VALUE timeout = argc == 1 ? argv[0] : Qnil;

    return io_wait_event(io, RUBY_IO_PRIORITY, timeout);
}

Waits until IO is priority and returns true or false when times out.

io.wait_readable → true or false

io.wait_readable(timeout) → true or false

ext/io/wait/wait.c View on GitHub

          
            static VALUE
io_wait_readable(int argc, VALUE *argv, VALUE io)
{
    rb_io_t *fptr;
#ifndef HAVE_RB_IO_WAIT
    struct timeval timerec;
    struct timeval *tv;
#endif

    GetOpenFile(io, fptr);
    rb_io_check_readable(fptr);

#ifndef HAVE_RB_IO_WAIT
    tv = get_timeout(argc, argv, &timerec);
#endif
    if (rb_io_read_pending(fptr)) return Qtrue;

#ifndef HAVE_RB_IO_WAIT
    if (wait_for_single_fd(fptr, RB_WAITFD_IN, tv)) {
        return io;
    }
    return Qnil;
#else
    rb_check_arity(argc, 0, 1);
    VALUE timeout = (argc == 1 ? argv[0] : Qnil);

    return io_wait_event(io, RUBY_IO_READABLE, timeout);
#endif
}

Waits until IO is readable and returns true, or false when times out. Returns true immediately when buffered data is available.

io.wait_writable → true or false

io.wait_writable(timeout) → true or false

ext/io/wait/wait.c View on GitHub

          
            static VALUE
io_wait_writable(int argc, VALUE *argv, VALUE io)
{
    rb_io_t *fptr;
#ifndef HAVE_RB_IO_WAIT
    struct timeval timerec;
    struct timeval *tv;
#endif

    GetOpenFile(io, fptr);
    rb_io_check_writable(fptr);

#ifndef HAVE_RB_IO_WAIT
    tv = get_timeout(argc, argv, &timerec);
    if (wait_for_single_fd(fptr, RB_WAITFD_OUT, tv)) {
        return io;
    }
    return Qnil;
#else
    rb_check_arity(argc, 0, 1);
    VALUE timeout = (argc == 1 ? argv[0] : Qnil);

    return io_wait_event(io, RUBY_IO_WRITABLE, timeout);
#endif
}

Waits until IO is writable and returns true or false when times out.

io.winsize → [rows, columns]

ext/io/console/console.c View on GitHub

          
            static VALUE
console_winsize(VALUE io)
{
    rb_io_t *fptr;
    int fd;
    rb_console_size_t ws;

    GetOpenFile(io, fptr);
    fd = GetWriteFD(fptr);
    if (!getwinsize(fd, &ws)) sys_fail_fptr(fptr);
    return rb_assoc_new(INT2NUM(winsize_row(&ws)), INT2NUM(winsize_col(&ws)));
}

Returns console size.

You must require ‘io/console’ to use this method.

io.winsize = [rows, columns]

ext/io/console/console.c View on GitHub

          
            static VALUE
console_set_winsize(VALUE io, VALUE size)
{
    rb_io_t *fptr;
    rb_console_size_t ws;
#if defined _WIN32
    HANDLE wh;
    int newrow, newcol;
    BOOL ret;
#endif
    VALUE row, col, xpixel, ypixel;
    const VALUE *sz;
    int fd;
    long sizelen;

    GetOpenFile(io, fptr);
    size = rb_Array(size);
    if ((sizelen = RARRAY_LEN(size)) != 2 && sizelen != 4) {
        rb_raise(rb_eArgError,
                 "wrong number of arguments (given %ld, expected 2 or 4)",
                 sizelen);
    }
    sz = RARRAY_CONST_PTR(size);
    row = sz[0], col = sz[1], xpixel = ypixel = Qnil;
    if (sizelen == 4) xpixel = sz[2], ypixel = sz[3];
    fd = GetWriteFD(fptr);
#if defined TIOCSWINSZ
    ws.ws_row = ws.ws_col = ws.ws_xpixel = ws.ws_ypixel = 0;
#define SET(m) ws.ws_##m = NIL_P(m) ? 0 : (unsigned short)NUM2UINT(m)
    SET(row);
    SET(col);
    SET(xpixel);
    SET(ypixel);
#undef SET
    if (!setwinsize(fd, &ws)) sys_fail_fptr(fptr);
#elif defined _WIN32
    wh = (HANDLE)rb_w32_get_osfhandle(fd);
#define SET(m) new##m = NIL_P(m) ? 0 : (unsigned short)NUM2UINT(m)
    SET(row);
    SET(col);
#undef SET
    if (!NIL_P(xpixel)) (void)NUM2UINT(xpixel);
    if (!NIL_P(ypixel)) (void)NUM2UINT(ypixel);
    if (!GetConsoleScreenBufferInfo(wh, &ws)) {
        rb_syserr_fail(LAST_ERROR, "GetConsoleScreenBufferInfo");
    }
    ws.dwSize.X = newcol;
    ret = SetConsoleScreenBufferSize(wh, ws.dwSize);
    ws.srWindow.Left = 0;
    ws.srWindow.Top = 0;
    ws.srWindow.Right = newcol-1;
    ws.srWindow.Bottom = newrow-1;
    if (!SetConsoleWindowInfo(wh, TRUE, &ws.srWindow)) {
        rb_syserr_fail(LAST_ERROR, "SetConsoleWindowInfo");
    }
    /* retry when shrinking buffer after shrunk window */
    if (!ret && !SetConsoleScreenBufferSize(wh, ws.dwSize)) {
        rb_syserr_fail(LAST_ERROR, "SetConsoleScreenBufferInfo");
    }
    /* remove scrollbar if possible */
    if (!SetConsoleWindowInfo(wh, TRUE, &ws.srWindow)) {
        rb_syserr_fail(LAST_ERROR, "SetConsoleWindowInfo");
    }
#endif
    return io;
}

Tries to set console size. The effect depends on the platform and the running environment.

You must require ‘io/console’ to use this method.

write(*objects) → integer

io.c View on GitHub

          
            static VALUE
io_write_m(int argc, VALUE *argv, VALUE io)
{
    if (argc != 1) {
        return io_writev(argc, argv, io);
    }
    else {
        VALUE str = argv[0];
        return io_write(io, str, 0);
    }
}

Writes each of the given objects to self, which must be opened for writing (see Modes); returns the total number bytes written; each of objects that is not a string is converted via method to_s:

$stdout.write('Hello', ', ', 'World!', "\n") # => 14
$stdout.write('foo', :bar, 2, "\n")          # => 8

Output:

Hello, World!
foobar2

ios.write_nonblock(string) → integer

ios.write_nonblock(string [, options]) → integer

io.rb View on GitHub

          
            # File tmp/rubies/ruby-3.1.3/io.rb, line 120
def write_nonblock(buf, exception: true)
  Primitive.io_write_nonblock(buf, exception)
end

Writes the given string to ios using the write(2) system call after O_NONBLOCK is set for the underlying file descriptor.

It returns the number of bytes written.

write_nonblock just calls the write(2) system call. It causes all errors the write(2) system call causes: Errno::EWOULDBLOCK, Errno::EINTR, etc. The result may also be smaller than string.length (partial write). The caller should care such errors and partial write.

If the exception is Errno::EWOULDBLOCK or Errno::EAGAIN, it is extended by IO::WaitWritable. So IO::WaitWritable can be used to rescue the exceptions for retrying write_nonblock.

# Creates a pipe.
r, w = IO.pipe

# write_nonblock writes only 65536 bytes and return 65536.
# (The pipe size is 65536 bytes on this environment.)
s = "a" * 100000
p w.write_nonblock(s)     #=> 65536

# write_nonblock cannot write a byte and raise EWOULDBLOCK (EAGAIN).
p w.write_nonblock("b")   # Resource temporarily unavailable (Errno::EAGAIN)

If the write buffer is not empty, it is flushed at first.

When write_nonblock raises an exception kind of IO::WaitWritable, write_nonblock should not be called until io is writable for avoiding busy loop. This can be done as follows.

begin
  result = io.write_nonblock(string)
rescue IO::WaitWritable, Errno::EINTR
  IO.select(nil, [io])
  retry
end

Note that this doesn’t guarantee to write all data in string. The length written is reported as result and it should be checked later.

On some platforms such as Windows, write_nonblock is not supported according to the kind of the IO object. In such cases, write_nonblock raises Errno::EBADF.

By specifying a keyword argument exception to false, you can indicate that write_nonblock should not raise an IO::WaitWritable exception, but return the symbol :wait_writable instead.

io/console

Example Files

Modes

Mode Specified as an Integer

Mode Specified As a String

Encodings

Open Options

Getline Options

Position

Line Number

What’s Here

Creating

Reading

Writing

Positioning

Iterating

Settings

Querying

Buffering

Low-Level Access

Other

IO.binread(name, [length [, offset]]) → string

File.binread(name, [length [, offset]]) → string

IO.binwrite(name, string, [offset]) → integer

IO.binwrite(name, string, [offset], open_args) → integer

File.binwrite(name, string, [offset]) → integer

File.binwrite(name, string, [offset], open_args) → integer

IO.console → #<File:/dev/tty>

IO.console(sym, *args)

console_size

IO.copy_stream(src, dst)

IO.copy_stream(src, dst, copy_length)

IO.copy_stream(src, dst, copy_length, src_offset)

default_console_size

IO.for_fd(fd, mode [, opt]) → io

IO.foreach(name, sep=$/ [, getline_args, open_args]) {|line| block } → nil

IO.foreach(name, limit [, getline_args, open_args]) {|line| block } → nil

IO.foreach(name, sep, limit [, getline_args, open_args]) {|line| block } → nil

IO.foreach(...) → an_enumerator

File.foreach(name, sep=$/ [, getline_args, open_args]) {|line| block } → nil

File.foreach(name, limit [, getline_args, open_args]) {|line| block } → nil

File.foreach(name, sep, limit [, getline_args, open_args]) {|line| block } → nil

File.foreach(...) → an_enumerator

IO.new(fd [, mode] [, opt]) → io

Open Mode

IO Open Mode

Options

Example 1

Example 2

IO.open(fd, mode="r" [, opt]) → io

IO.open(fd, mode="r" [, opt]) {|io| block } → obj

IO.pipe → [read_io, write_io]

IO.pipe(ext_enc) → [read_io, write_io]

IO.pipe("ext_enc:int_enc" [, opt]) → [read_io, write_io]

IO.pipe(ext_enc, int_enc [, opt]) → [read_io, write_io]

IO.pipe(...) {|read_io, write_io| ... }

IO.popen([env,] cmd, mode="r" [, opt]) → io

IO.popen([env,] cmd, mode="r" [, opt]) {|io| block } → obj

IO.read(name, [length [, offset]] [, opt]) → string

File.read(name, [length [, offset]] [, opt]) → string

Options

IO.readlines(name, sep=$/ [, getline_args, open_args]) → array

IO.readlines(name, limit [, getline_args, open_args]) → array

IO.readlines(name, sep, limit [, getline_args, open_args]) → array

File.readlines(name, sep=$/ [, getline_args, open_args]) → array

File.readlines(name, limit [, getline_args, open_args]) → array

File.readlines(name, sep, limit [, getline_args, open_args]) → array

Options for getline

IO.select(read_array [, write_array [, error_array [, timeout]]]) → array or nil

Parameters

Example

IO.sysopen(path, [mode, [perm]]) → integer

IO.try_convert(object) → new_io or nil

IO.write(name, string [, offset]) → integer

IO.write(name, string [, offset] [, opt]) → integer

File.write(name, string [, offset]) → integer

File.write(name, string [, offset] [, opt]) → integer

self << object → self

ios.advise(advice, offset=0, len=0) → nil

io.autoclose = bool → true or false

`IO` Open Mode