Equivalent to << with argument n * 12.
Scrolls the entire scrolls forward n lines.
You must require ‘io/console’ to use this method.
Scrolls the entire scrolls backward n lines.
You must require ‘io/console’ to use this method.
Waits until IO is priority and returns a truthy value or a falsy value when times out. Priority data is sent and received using the Socket::MSG_OOB flag and is typically limited to streams.
You must require ‘io/wait’ to use this method.
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.
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.
This method is called when the parser found syntax error.
Accepts an incoming connection using accept(2) after O_NONBLOCK is set for the underlying file descriptor. It returns an array containing the accepted socket for the incoming connection, client_socket, and an Addrinfo, client_addrinfo.
# In one script, start this first require 'socket' include Socket::Constants socket = Socket.new(AF_INET, SOCK_STREAM, 0) sockaddr = Socket.sockaddr_in(2200, 'localhost') socket.bind(sockaddr) socket.listen(5) begin # emulate blocking accept client_socket, client_addrinfo = socket.accept_nonblock rescue IO::WaitReadable, Errno::EINTR IO.select([socket]) retry end puts "The client said, '#{client_socket.readline.chomp}'" client_socket.puts "Hello from script one!" socket.close # In another script, start this second require 'socket' include Socket::Constants socket = Socket.new(AF_INET, SOCK_STREAM, 0) sockaddr = Socket.sockaddr_in(2200, 'localhost') socket.connect(sockaddr) socket.puts "Hello from script 2." puts "The server said, '#{socket.readline.chomp}'" socket.close
Refer to Socket#accept for the exceptions that may be thrown if the call to accept_nonblock fails.
Socket#accept_nonblock may raise any error corresponding to accept(2) failure, including Errno::EWOULDBLOCK.
If the exception is Errno::EWOULDBLOCK, Errno::EAGAIN, Errno::ECONNABORTED or Errno::EPROTO, it is extended by IO::WaitReadable. So IO::WaitReadable can be used to rescue the exceptions for retrying accept_nonblock.
By specifying a keyword argument exception to false, you can indicate that accept_nonblock should not raise an IO::WaitReadable exception, but return the symbol :wait_readable instead.
Requests a connection to be made on the given remote_sockaddr after O_NONBLOCK is set for the underlying file descriptor. Returns 0 if successful, otherwise an exception is raised.
remote_sockaddr - the struct sockaddr contained in a string or Addrinfo object
# Pull down Google's web page require 'socket' include Socket::Constants socket = Socket.new(AF_INET, SOCK_STREAM, 0) sockaddr = Socket.sockaddr_in(80, 'www.google.com') begin # emulate blocking connect socket.connect_nonblock(sockaddr) rescue IO::WaitWritable IO.select(nil, [socket]) # wait 3-way handshake completion begin socket.connect_nonblock(sockaddr) # check connection failure rescue Errno::EISCONN end end socket.write("GET / HTTP/1.0\r\n\r\n") results = socket.read
Refer to Socket#connect for the exceptions that may be thrown if the call to connect_nonblock fails.
Socket#connect_nonblock may raise any error corresponding to connect(2) failure, including Errno::EINPROGRESS.
If the exception is Errno::EINPROGRESS, it is extended by IO::WaitWritable. So IO::WaitWritable can be used to rescue the exceptions for retrying connect_nonblock.
By specifying a keyword argument exception to false, you can indicate that connect_nonblock should not raise an IO::WaitWritable exception, but return the symbol :wait_writable instead.
Packs port and host as an AF_INET/AF_INET6 sockaddr string.
Socket.sockaddr_in(80, "127.0.0.1") #=> "\x02\x00\x00P\x7F\x00\x00\x01\x00\x00\x00\x00\x00\x00\x00\x00" Socket.sockaddr_in(80, "::1") #=> "\n\x00\x00P\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x01\x00\x00\x00\x00"
Packs path as an AF_UNIX sockaddr string.
Socket.sockaddr_un("/tmp/sock") #=> "\x01\x00/tmp/sock\x00\x00..."
Returns an Addrinfo object for local address obtained by getsockname.
Note that addrinfo.protocol is filled by 0.
TCPSocket.open("www.ruby-lang.org", 80) {|s| p s.local_address #=> #<Addrinfo: 192.168.0.129:36873 TCP> } TCPServer.open("127.0.0.1", 1512) {|serv| p serv.local_address #=> #<Addrinfo: 127.0.0.1:1512 TCP> }
sendmsg_nonblock sends a message using sendmsg(2) system call in non-blocking manner.
It is similar to BasicSocket#sendmsg but the non-blocking flag is set before the system call and it doesn’t retry the system call.
By specifying a keyword argument exception to false, you can indicate that sendmsg_nonblock should not raise an IO::WaitWritable exception, but return the symbol :wait_writable instead.
Receives up to maxlen bytes from socket using recvfrom(2) after O_NONBLOCK is set for the underlying file descriptor. flags is zero or more of the MSG_ options. The result, mesg, is the data received.
When recvfrom(2) returns 0, Socket#recv_nonblock returns nil. In most cases it means the connection was closed, but for UDP connections it may mean an empty packet was received, as the underlying API makes it impossible to distinguish these two cases.
maxlen - the number of bytes to receive from the socket
flags - zero or more of the MSG_ options
buf - destination String buffer
options - keyword hash, supporting ‘exception: false`
serv = TCPServer.new("127.0.0.1", 0) af, port, host, addr = serv.addr c = TCPSocket.new(addr, port) s = serv.accept c.send "aaa", 0 begin # emulate blocking recv. p s.recv_nonblock(10) #=> "aaa" rescue IO::WaitReadable IO.select([s]) retry end
Refer to Socket#recvfrom for the exceptions that may be thrown if the call to recv_nonblock fails.
BasicSocket#recv_nonblock may raise any error corresponding to recvfrom(2) failure, including Errno::EWOULDBLOCK.
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 recv_nonblock.
By specifying a keyword argument exception to false, you can indicate that recv_nonblock should not raise an IO::WaitReadable exception, but return the symbol :wait_readable instead.
recvmsg receives a message using recvmsg(2) system call in non-blocking manner.
It is similar to BasicSocket#recvmsg but non-blocking flag is set before the system call and it doesn’t retry the system call.
By specifying a keyword argument exception to false, you can indicate that recvmsg_nonblock should not raise an IO::WaitReadable exception, but return the symbol :wait_readable instead.
creates a socket connected to the address of self.
If one or more arguments given as local_addr_args, it is used as the local address of the socket. local_addr_args is given for family_addrinfo to obtain actual address.
If local_addr_args is not given, the local address of the socket is not bound.
The optional last argument opts is options represented by a hash. opts may have following options:
specify the timeout in seconds.
If a block is given, it is called with the socket and the value of the block is returned. The socket is returned otherwise.
Addrinfo.tcp("www.ruby-lang.org", 80).connect_from("0.0.0.0", 4649) {|s| s.print "GET / HTTP/1.0\r\nHost: www.ruby-lang.org\r\n\r\n" puts s.read } # Addrinfo object can be taken for the argument. Addrinfo.tcp("www.ruby-lang.org", 80).connect_from(Addrinfo.tcp("0.0.0.0", 4649)) {|s| s.print "GET / HTTP/1.0\r\nHost: www.ruby-lang.org\r\n\r\n" puts s.read }
returns a string which shows the sockaddr in addrinfo with human-readable form.
Addrinfo.tcp("localhost", 80).inspect_sockaddr #=> "127.0.0.1:80" Addrinfo.tcp("ip6-localhost", 80).inspect_sockaddr #=> "[::1]:80" Addrinfo.unix("/tmp/sock").inspect_sockaddr #=> "/tmp/sock"
Returns true for IPv4 private address (10.0.0.0/8, 172.16.0.0/12, 192.168.0.0/16). It returns false otherwise.
Returns true for IPv6 link local address (fe80::/10). It returns false otherwise.
Returns true for IPv6 site local address (fec0::/10). It returns false otherwise.
Accepts an incoming connection using accept(2) after O_NONBLOCK is set for the underlying file descriptor. It returns an accepted TCPSocket for the incoming connection.
require 'socket' serv = TCPServer.new(2202) begin # emulate blocking accept sock = serv.accept_nonblock rescue IO::WaitReadable, Errno::EINTR IO.select([serv]) retry end # sock is an accepted socket.
Refer to Socket#accept for the exceptions that may be thrown if the call to TCPServer#accept_nonblock fails.
TCPServer#accept_nonblock may raise any error corresponding to accept(2) failure, including Errno::EWOULDBLOCK.
If the exception is Errno::EWOULDBLOCK, Errno::EAGAIN, Errno::ECONNABORTED, Errno::EPROTO, it is extended by IO::WaitReadable. So IO::WaitReadable can be used to rescue the exceptions for retrying accept_nonblock.
By specifying a keyword argument exception to false, you can indicate that accept_nonblock should not raise an IO::WaitReadable exception, but return the symbol :wait_readable instead.
Accepts an incoming connection using accept(2) after O_NONBLOCK is set for the underlying file descriptor. It returns an accepted UNIXSocket for the incoming connection.
require 'socket' serv = UNIXServer.new("/tmp/sock") begin # emulate blocking accept sock = serv.accept_nonblock rescue IO::WaitReadable, Errno::EINTR IO.select([serv]) retry end # sock is an accepted socket.
Refer to Socket#accept for the exceptions that may be thrown if the call to UNIXServer#accept_nonblock fails.
UNIXServer#accept_nonblock may raise any error corresponding to accept(2) failure, including Errno::EWOULDBLOCK.
If the exception is Errno::EWOULDBLOCK, Errno::EAGAIN, Errno::ECONNABORTED or Errno::EPROTO, it is extended by IO::WaitReadable. So IO::WaitReadable can be used to rescue the exceptions for retrying accept_nonblock.
By specifying a keyword argument exception to false, you can indicate that accept_nonblock should not raise an IO::WaitReadable exception, but return the symbol :wait_readable instead.
Returns the substring that precedes the matched substring from the most recent match attempt if it was successful, or nil otherwise; see [Basic Match Values]:
scanner = StringScanner.new('foobarbaz') scanner.pre_match # => nil scanner.pos = 3 scanner.exist?(/baz/) # => 6 scanner.pre_match # => "foobar" # Substring of entire string, not just target string. scanner.exist?(/nope/) # => nil scanner.pre_match # => nil
Reads at most maxlen bytes from the ARGF stream in non-blocking mode.