returns a list of addrinfo objects as an array.
This method converts nodename (hostname) and service (port) to addrinfo. Since the conversion is not unique, the result is a list of addrinfo objects.
nodename or service can be nil if no conversion intended.
family, socktype and protocol are hint for preferred protocol. If the result will be used for a socket with SOCK_STREAM, SOCK_STREAM should be specified as socktype. If so, Addrinfo.getaddrinfo returns addrinfo list appropriate for SOCK_STREAM. If they are omitted or nil is given, the result is not restricted.
Similarly, PF_INET6 as family restricts for IPv6.
flags should be bitwise OR of Socket::AI_??? constants such as follows. Note that the exact list of the constants depends on OS.
AI_PASSIVE Get address to use with bind() AI_CANONNAME Fill in the canonical name AI_NUMERICHOST Prevent host name resolution AI_NUMERICSERV Prevent service name resolution AI_V4MAPPED Accept IPv4-mapped IPv6 addresses AI_ALL Allow all addresses AI_ADDRCONFIG Accept only if any address is assigned
Note that socktype should be specified whenever application knows the usage of the address. Some platform causes an error when socktype is omitted and servname is specified as an integer because some port numbers, 512 for example, are ambiguous without socktype.
Addrinfo.getaddrinfo("www.kame.net", 80, nil, :STREAM) #=> [#<Addrinfo: 203.178.141.194:80 TCP (www.kame.net)>, # #<Addrinfo: [2001:200:dff:fff1:216:3eff:feb1:44d7]:80 TCP (www.kame.net)>]
Returns the method invoke kind.
tobj = WIN32OLE_TYPE.new('Microsoft Excel 9.0 Object Library', 'Workbooks') method = WIN32OLE_METHOD.new(tobj, 'Add') puts method.invkind # => 1
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.
Formats and writes to ios, converting parameters under control of the format string. See Kernel#sprintf for details.
Creates or retrieves cached CSV objects. For arguments and options, see CSV.new.
This API is not Ractor-safe.
With no block given, returns a CSV object.
The first call to instance creates and caches a CSV object:
s0 = 's0' csv0 = CSV.instance(s0) csv0.class # => CSV
Subsequent calls to instance with that same string or io retrieve that same cached object:
csv1 = CSV.instance(s0) csv1.class # => CSV csv1.equal?(csv0) # => true # Same CSV object
A subsequent call to instance with a different string or io creates and caches a different CSV object.
s1 = 's1' csv2 = CSV.instance(s1) csv2.equal?(csv0) # => false # Different CSV object
All the cached objects remains available:
csv3 = CSV.instance(s0) csv3.equal?(csv0) # true # Same CSV object csv4 = CSV.instance(s1) csv4.equal?(csv2) # true # Same CSV object
When a block is given, calls the block with the created or retrieved CSV object; returns the block’s return value:
CSV.instance(s0) {|csv| :foo } # => :foo
Returns the priority of thr. Default is inherited from the current thread which creating the new thread, or zero for the initial main thread; higher-priority thread will run more frequently than lower-priority threads (but lower-priority threads can also run).
This is just hint for Ruby thread scheduler. It may be ignored on some platform.
Thread.current.priority #=> 0
Sets the priority of thr to integer. Higher-priority threads will run more frequently than lower-priority threads (but lower-priority threads can also run).
This is just hint for Ruby thread scheduler. It may be ignored on some platform.
count1 = count2 = 0 a = Thread.new do loop { count1 += 1 } end a.priority = -1 b = Thread.new do loop { count2 += 1 } end b.priority = -2 sleep 1 #=> 1 count1 #=> 622504 count2 #=> 5832
Equivalent to:
io.write(sprintf(string, obj, ...))
or
$stdout.write(sprintf(string, obj, ...))
Prints each object in turn to $stdout. If the output field separator ($,) is not nil, its contents will appear between each field. If the output record separator ($\) is not nil, it will be appended to the output. If no arguments are given, prints $_. Objects that aren’t strings will be converted by calling their to_s method.
print "cat", [1,2,3], 99, "\n" $, = ", " $\ = "\n" print "cat", [1,2,3], 99
produces:
cat12399 cat, 1, 2, 3, 99
Returns the string resulting from applying format_string to any additional arguments. Within the format string, any characters other than format sequences are copied to the result.
The syntax of a format sequence is as follows.
%[flags][width][.precision]type
A format sequence consists of a percent sign, followed by optional flags, width, and precision indicators, then terminated with a field type character. The field type controls how the corresponding sprintf argument is to be interpreted, while the flags modify that interpretation.
The field type characters are:
Field | Integer Format
------+--------------------------------------------------------------
b | Convert argument as a binary number.
| Negative numbers will be displayed as a two's complement
| prefixed with `..1'.
B | Equivalent to `b', but uses an uppercase 0B for prefix
| in the alternative format by #.
d | Convert argument as a decimal number.
i | Identical to `d'.
o | Convert argument as an octal number.
| Negative numbers will be displayed as a two's complement
| prefixed with `..7'.
u | Identical to `d'.
x | Convert argument as a hexadecimal number.
| Negative numbers will be displayed as a two's complement
| prefixed with `..f' (representing an infinite string of
| leading 'ff's).
X | Equivalent to `x', but uses uppercase letters.
Field | Float Format
------+--------------------------------------------------------------
e | Convert floating point argument into exponential notation
| with one digit before the decimal point as [-]d.dddddde[+-]dd.
| The precision specifies the number of digits after the decimal
| point (defaulting to six).
E | Equivalent to `e', but uses an uppercase E to indicate
| the exponent.
f | Convert floating point argument as [-]ddd.dddddd,
| where the precision specifies the number of digits after
| the decimal point.
g | Convert a floating point number using exponential form
| if the exponent is less than -4 or greater than or
| equal to the precision, or in dd.dddd form otherwise.
| The precision specifies the number of significant digits.
G | Equivalent to `g', but use an uppercase `E' in exponent form.
a | Convert floating point argument as [-]0xh.hhhhp[+-]dd,
| which is consisted from optional sign, "0x", fraction part
| as hexadecimal, "p", and exponential part as decimal.
A | Equivalent to `a', but use uppercase `X' and `P'.
Field | Other Format
------+--------------------------------------------------------------
c | Argument is the numeric code for a single character or
| a single character string itself.
p | The valuing of argument.inspect.
s | Argument is a string to be substituted. If the format
| sequence contains a precision, at most that many characters
| will be copied.
% | A percent sign itself will be displayed. No argument taken.
The flags modifies the behavior of the formats. The flag characters are:
Flag | Applies to | Meaning
---------+---------------+-----------------------------------------
space | bBdiouxX | Leave a space at the start of
| aAeEfgG | non-negative numbers.
| (numeric fmt) | For `o', `x', `X', `b' and `B', use
| | a minus sign with absolute value for
| | negative values.
---------+---------------+-----------------------------------------
(digit)$ | all | Specifies the absolute argument number
| | for this field. Absolute and relative
| | argument numbers cannot be mixed in a
| | sprintf string.
---------+---------------+-----------------------------------------
# | bBoxX | Use an alternative format.
| aAeEfgG | For the conversions `o', increase the precision
| | until the first digit will be `0' if
| | it is not formatted as complements.
| | For the conversions `x', `X', `b' and `B'
| | on non-zero, prefix the result with ``0x'',
| | ``0X'', ``0b'' and ``0B'', respectively.
| | For `a', `A', `e', `E', `f', `g', and 'G',
| | force a decimal point to be added,
| | even if no digits follow.
| | For `g' and 'G', do not remove trailing zeros.
---------+---------------+-----------------------------------------
+ | bBdiouxX | Add a leading plus sign to non-negative
| aAeEfgG | numbers.
| (numeric fmt) | For `o', `x', `X', `b' and `B', use
| | a minus sign with absolute value for
| | negative values.
---------+---------------+-----------------------------------------
- | all | Left-justify the result of this conversion.
---------+---------------+-----------------------------------------
0 (zero) | bBdiouxX | Pad with zeros, not spaces.
| aAeEfgG | For `o', `x', `X', `b' and `B', radix-1
| (numeric fmt) | is used for negative numbers formatted as
| | complements.
---------+---------------+-----------------------------------------
* | all | Use the next argument as the field width.
| | If negative, left-justify the result. If the
| | asterisk is followed by a number and a dollar
| | sign, use the indicated argument as the width.
Examples of flags:
# `+' and space flag specifies the sign of non-negative numbers. sprintf("%d", 123) #=> "123" sprintf("%+d", 123) #=> "+123" sprintf("% d", 123) #=> " 123" # `#' flag for `o' increases number of digits to show `0'. # `+' and space flag changes format of negative numbers. sprintf("%o", 123) #=> "173" sprintf("%#o", 123) #=> "0173" sprintf("%+o", -123) #=> "-173" sprintf("%o", -123) #=> "..7605" sprintf("%#o", -123) #=> "..7605" # `#' flag for `x' add a prefix `0x' for non-zero numbers. # `+' and space flag disables complements for negative numbers. sprintf("%x", 123) #=> "7b" sprintf("%#x", 123) #=> "0x7b" sprintf("%+x", -123) #=> "-7b" sprintf("%x", -123) #=> "..f85" sprintf("%#x", -123) #=> "0x..f85" sprintf("%#x", 0) #=> "0" # `#' for `X' uses the prefix `0X'. sprintf("%X", 123) #=> "7B" sprintf("%#X", 123) #=> "0X7B" # `#' flag for `b' add a prefix `0b' for non-zero numbers. # `+' and space flag disables complements for negative numbers. sprintf("%b", 123) #=> "1111011" sprintf("%#b", 123) #=> "0b1111011" sprintf("%+b", -123) #=> "-1111011" sprintf("%b", -123) #=> "..10000101" sprintf("%#b", -123) #=> "0b..10000101" sprintf("%#b", 0) #=> "0" # `#' for `B' uses the prefix `0B'. sprintf("%B", 123) #=> "1111011" sprintf("%#B", 123) #=> "0B1111011" # `#' for `e' forces to show the decimal point. sprintf("%.0e", 1) #=> "1e+00" sprintf("%#.0e", 1) #=> "1.e+00" # `#' for `f' forces to show the decimal point. sprintf("%.0f", 1234) #=> "1234" sprintf("%#.0f", 1234) #=> "1234." # `#' for `g' forces to show the decimal point. # It also disables stripping lowest zeros. sprintf("%g", 123.4) #=> "123.4" sprintf("%#g", 123.4) #=> "123.400" sprintf("%g", 123456) #=> "123456" sprintf("%#g", 123456) #=> "123456."
The field width is an optional integer, followed optionally by a period and a precision. The width specifies the minimum number of characters that will be written to the result for this field.
Examples of width:
# padding is done by spaces, width=20 # 0 or radix-1. <------------------> sprintf("%20d", 123) #=> " 123" sprintf("%+20d", 123) #=> " +123" sprintf("%020d", 123) #=> "00000000000000000123" sprintf("%+020d", 123) #=> "+0000000000000000123" sprintf("% 020d", 123) #=> " 0000000000000000123" sprintf("%-20d", 123) #=> "123 " sprintf("%-+20d", 123) #=> "+123 " sprintf("%- 20d", 123) #=> " 123 " sprintf("%020x", -123) #=> "..ffffffffffffffff85"
For numeric fields, the precision controls the number of decimal places displayed. For string fields, the precision determines the maximum number of characters to be copied from the string. (Thus, the format sequence %10.10s will always contribute exactly ten characters to the result.)
Examples of precisions:
# precision for `d', 'o', 'x' and 'b' is # minimum number of digits <------> sprintf("%20.8d", 123) #=> " 00000123" sprintf("%20.8o", 123) #=> " 00000173" sprintf("%20.8x", 123) #=> " 0000007b" sprintf("%20.8b", 123) #=> " 01111011" sprintf("%20.8d", -123) #=> " -00000123" sprintf("%20.8o", -123) #=> " ..777605" sprintf("%20.8x", -123) #=> " ..ffff85" sprintf("%20.8b", -11) #=> " ..110101" # "0x" and "0b" for `#x' and `#b' is not counted for # precision but "0" for `#o' is counted. <------> sprintf("%#20.8d", 123) #=> " 00000123" sprintf("%#20.8o", 123) #=> " 00000173" sprintf("%#20.8x", 123) #=> " 0x0000007b" sprintf("%#20.8b", 123) #=> " 0b01111011" sprintf("%#20.8d", -123) #=> " -00000123" sprintf("%#20.8o", -123) #=> " ..777605" sprintf("%#20.8x", -123) #=> " 0x..ffff85" sprintf("%#20.8b", -11) #=> " 0b..110101" # precision for `e' is number of # digits after the decimal point <------> sprintf("%20.8e", 1234.56789) #=> " 1.23456789e+03" # precision for `f' is number of # digits after the decimal point <------> sprintf("%20.8f", 1234.56789) #=> " 1234.56789000" # precision for `g' is number of # significant digits <-------> sprintf("%20.8g", 1234.56789) #=> " 1234.5679" # <-------> sprintf("%20.8g", 123456789) #=> " 1.2345679e+08" # precision for `s' is # maximum number of characters <------> sprintf("%20.8s", "string test") #=> " string t"
Examples:
sprintf("%d %04x", 123, 123) #=> "123 007b" sprintf("%08b '%4s'", 123, 123) #=> "01111011 ' 123'" sprintf("%1$*2$s %2$d %1$s", "hello", 8) #=> " hello 8 hello" sprintf("%1$*2$s %2$d", "hello", -8) #=> "hello -8" sprintf("%+g:% g:%-g", 1.23, 1.23, 1.23) #=> "+1.23: 1.23:1.23" sprintf("%u", -123) #=> "-123"
For more complex formatting, Ruby supports a reference by name. %<name>s style uses format style, but %{name} style doesn’t.
Examples:
sprintf("%<foo>d : %<bar>f", { :foo => 1, :bar => 2 }) #=> 1 : 2.000000 sprintf("%{foo}f", { :foo => 1 }) # => "1f"
Returns an array containing the items in self:
(0..4).to_a # => [0, 1, 2, 3, 4]
Enumerable#entries is an alias for Enumerable#to_a.
Returns true if coverage stats are currently being collected (after Coverage.start call, but before Coverage.result call)
Returns system configuration variable using confstr().
name should be a constant under Etc which begins with CS_.
The return value is a string or nil. nil means no configuration-defined value. (confstr() returns 0 but errno is not set.)
Etc.confstr(Etc::CS_PATH) #=> "/bin:/usr/bin" # GNU/Linux Etc.confstr(Etc::CS_GNU_LIBC_VERSION) #=> "glibc 2.18" Etc.confstr(Etc::CS_GNU_LIBPTHREAD_VERSION) #=> "NPTL 2.18"
Returns self, for backward compatibility.
Returns current status of GC stress mode.
Updates the GC stress mode.
When stress mode is enabled, the GC is invoked at every GC opportunity: all memory and object allocations.
Enabling stress mode will degrade performance, it is only for debugging.
flag can be true, false, or an integer bit-ORed following flags.
0x01:: no major GC 0x02:: no immediate sweep 0x04:: full mark after malloc/calloc/realloc
If src is not same as dest, copies it and changes the permission mode to mode. If dest is a directory, destination is dest/src. This method removes destination before copy.
FileUtils.install 'ruby', '/usr/local/bin/ruby', mode: 0755, verbose: true FileUtils.install 'lib.rb', '/usr/local/lib/ruby/site_ruby', verbose: true
If src is not same as dest, copies it and changes the permission mode to mode. If dest is a directory, destination is dest/src. This method removes destination before copy.
FileUtils.install 'ruby', '/usr/local/bin/ruby', mode: 0755, verbose: true FileUtils.install 'lib.rb', '/usr/local/lib/ruby/site_ruby', verbose: true
Top level install helper method. Allows you to install gems interactively:
% irb >> Gem.install "minitest" Fetching: minitest-5.14.0.gem (100%) => [#<Gem::Specification:0x1013b4528 @name="minitest", ...>]
Returns the singleton instance.
Gets the scheduling priority for specified process, process group, or user. kind indicates the kind of entity to find: one of Process::PRIO_PGRP, Process::PRIO_USER, or Process::PRIO_PROCESS. integer is an id indicating the particular process, process group, or user (an id of 0 means current). Lower priorities are more favorable for scheduling. Not available on all platforms.
Process.getpriority(Process::PRIO_USER, 0) #=> 19 Process.getpriority(Process::PRIO_PROCESS, 0) #=> 19
See Process.getpriority.
Process.setpriority(Process::PRIO_USER, 0, 19) #=> 0 Process.setpriority(Process::PRIO_PROCESS, 0, 19) #=> 0 Process.getpriority(Process::PRIO_USER, 0) #=> 19 Process.getpriority(Process::PRIO_PROCESS, 0) #=> 19
Returns the value of the given instance variable, or nil if the instance variable is not set. The @ part of the variable name should be included for regular instance variables. Throws a NameError exception if the supplied symbol is not valid as an instance variable name. String arguments are converted to symbols.
class Fred def initialize(p1, p2) @a, @b = p1, p2 end end fred = Fred.new('cat', 99) fred.instance_variable_get(:@a) #=> "cat" fred.instance_variable_get("@b") #=> 99
Sets the instance variable named by symbol to the given object. This may circumvent the encapsulation intended by the author of the class, so it should be used with care. The variable does not have to exist prior to this call. If the instance variable name is passed as a string, that string is converted to a symbol.
class Fred def initialize(p1, p2) @a, @b = p1, p2 end end fred = Fred.new('cat', 99) fred.instance_variable_set(:@a, 'dog') #=> "dog" fred.instance_variable_set(:@c, 'cat') #=> "cat" fred.inspect #=> "#<Fred:0x401b3da8 @a=\"dog\", @b=99, @c=\"cat\">"
Removes the named instance variable from obj, returning that variable’s value. String arguments are converted to symbols.
class Dummy attr_reader :var def initialize @var = 99 end def remove remove_instance_variable(:@var) end end d = Dummy.new d.var #=> 99 d.remove #=> 99 d.var #=> nil