Use Addrinfo#getnameinfo instead. This method is deprecated for the following reasons:
Uncommon address representation: 4/16-bytes binary string to represent IPv4/IPv6 address.
gethostbyaddr() may take a long time and it may block other threads. (GVL cannot be released since gethostbyname() is not thread safe.)
This method uses gethostbyname() function already removed from POSIX.
This method obtains the host information for address.
p Socket.gethostbyaddr([221,186,184,68].pack("CCCC"))
#=> ["carbon.ruby-lang.org", [], 2, "\xDD\xBA\xB8D"]
p Socket.gethostbyaddr([127,0,0,1].pack("CCCC"))
["localhost", [], 2, "\x7F\x00\x00\x01"]
p Socket.gethostbyaddr(([0]*15+[1]).pack("C"*16))
#=> ["localhost", ["ip6-localhost", "ip6-loopback"], 10,
"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x01"]
Return a string describing this IPSocket object.
creates a listening socket bound to self.
returns a string which shows addrinfo in human-readable form.
Addrinfo.tcp("localhost", 80).inspect #=> "#<Addrinfo: 127.0.0.1:80 TCP (localhost)>" Addrinfo.unix("/tmp/sock").inspect #=> "#<Addrinfo: /tmp/sock SOCK_STREAM>"
returns the socket type as an integer.
Addrinfo.tcp("localhost", 80).protocol == Socket::IPPROTO_TCP #=> true
returns the canonical name as a string.
nil is returned if no canonical name.
The canonical name is set by Addrinfo.getaddrinfo when AI_CANONNAME is specified.
list = Addrinfo.getaddrinfo("www.ruby-lang.org", 80, :INET, :STREAM, nil, Socket::AI_CANONNAME) p list[0] #=> #<Addrinfo: 221.186.184.68:80 TCP carbon.ruby-lang.org (www.ruby-lang.org)> p list[0].canonname #=> "carbon.ruby-lang.org"
Listens for connections, using the specified int as the backlog. A call to listen only applies if the socket is of type SOCK_STREAM or SOCK_SEQPACKET.
backlog - the maximum length of the queue for pending connections.
require 'socket' include Socket::Constants socket = Socket.new( AF_INET, SOCK_STREAM, 0 ) sockaddr = Socket.pack_sockaddr_in( 2200, 'localhost' ) socket.bind( sockaddr ) socket.listen( 5 )
require 'socket' include Socket::Constants socket = Socket.new( AF_INET, SOCK_STREAM, 0 ) socket.listen( 1 )
On unix based systems the above will work because a new sockaddr struct is created on the address ADDR_ANY, for an arbitrary port number as handed off by the kernel. It will not work on Windows, because Windows requires that the socket is bound by calling bind before it can listen.
If the backlog amount exceeds the implementation-dependent maximum queue length, the implementation’s maximum queue length will be used.
On unix-based based systems the following system exceptions may be raised if the call to listen fails:
Errno::EBADF - the socket argument is not a valid file descriptor
Errno::EDESTADDRREQ - the socket is not bound to a local address, and the protocol does not support listening on an unbound socket
Errno::EINVAL - the socket is already connected
Errno::ENOTSOCK - the socket argument does not refer to a socket
Errno::EOPNOTSUPP - the socket protocol does not support listen
Errno::EACCES - the calling process does not have appropriate privileges
Errno::EINVAL - the socket has been shut down
Errno::ENOBUFS - insufficient resources are available in the system to complete the call
On Windows systems the following system exceptions may be raised if the call to listen fails:
Errno::ENETDOWN - the network is down
Errno::EADDRINUSE - the socket’s local address is already in use. This usually occurs during the execution of bind but could be delayed if the call to bind was to a partially wildcard address (involving ADDR_ANY) and if a specific address needs to be committed at the time of the call to listen
Errno::EINPROGRESS - a Windows Sockets 1.1 call is in progress or the service provider is still processing a callback function
Errno::EINVAL - the socket has not been bound with a call to bind.
Errno::EISCONN - the socket is already connected
Errno::EMFILE - no more socket descriptors are available
Errno::ENOBUFS - no buffer space is available
Errno::ENOTSOC - socket is not a socket
Errno::EOPNOTSUPP - the referenced socket is not a type that supports the listen method
listen manual pages on unix-based systems
listen function in Microsoft’s Winsock functions reference
Listens for connections, using the specified int as the backlog. A call to listen only applies if the socket is of type SOCK_STREAM or SOCK_SEQPACKET.
backlog - the maximum length of the queue for pending connections.
require 'socket' include Socket::Constants socket = Socket.new( AF_INET, SOCK_STREAM, 0 ) sockaddr = Socket.pack_sockaddr_in( 2200, 'localhost' ) socket.bind( sockaddr ) socket.listen( 5 )
require 'socket' include Socket::Constants socket = Socket.new( AF_INET, SOCK_STREAM, 0 ) socket.listen( 1 )
On unix based systems the above will work because a new sockaddr struct is created on the address ADDR_ANY, for an arbitrary port number as handed off by the kernel. It will not work on Windows, because Windows requires that the socket is bound by calling bind before it can listen.
If the backlog amount exceeds the implementation-dependent maximum queue length, the implementation’s maximum queue length will be used.
On unix-based based systems the following system exceptions may be raised if the call to listen fails:
Errno::EBADF - the socket argument is not a valid file descriptor
Errno::EDESTADDRREQ - the socket is not bound to a local address, and the protocol does not support listening on an unbound socket
Errno::EINVAL - the socket is already connected
Errno::ENOTSOCK - the socket argument does not refer to a socket
Errno::EOPNOTSUPP - the socket protocol does not support listen
Errno::EACCES - the calling process does not have appropriate privileges
Errno::EINVAL - the socket has been shut down
Errno::ENOBUFS - insufficient resources are available in the system to complete the call
On Windows systems the following system exceptions may be raised if the call to listen fails:
Errno::ENETDOWN - the network is down
Errno::EADDRINUSE - the socket’s local address is already in use. This usually occurs during the execution of bind but could be delayed if the call to bind was to a partially wildcard address (involving ADDR_ANY) and if a specific address needs to be committed at the time of the call to listen
Errno::EINPROGRESS - a Windows Sockets 1.1 call is in progress or the service provider is still processing a callback function
Errno::EINVAL - the socket has not been bound with a call to bind.
Errno::EISCONN - the socket is already connected
Errno::EMFILE - no more socket descriptors are available
Errno::ENOBUFS - no buffer space is available
Errno::ENOTSOC - socket is not a socket
Errno::EOPNOTSUPP - the referenced socket is not a type that supports the listen method
listen manual pages on unix-based systems
listen function in Microsoft’s Winsock functions reference
Use Addrinfo.getaddrinfo instead. This method is deprecated for the following reasons:
The 3rd element of the result is the address family of the first address. The address families of the rest of the addresses are not returned.
gethostbyname() may take a long time and it may block other threads. (GVL cannot be released since gethostbyname() is not thread safe.)
This method uses gethostbyname() function already removed from POSIX.
This method lookups host information by hostname.
TCPSocket.gethostbyname("localhost") #=> ["localhost", ["hal"], 2, "127.0.0.1"]
Returns underlying string:
StringIO.open('foo') do |strio| p strio.string strio.string = 'bar' p strio.string end
Output:
"foo" "bar"
Related: StringIO#string= (assigns the underlying string).
Assigns the underlying string as other_string, and sets position to zero; returns other_string:
StringIO.open('foo') do |strio| p strio.string strio.string = 'bar' p strio.string end
Output:
"foo" "bar"
Related: StringIO#string (returns the underlying string).
Returns the string being scanned.
Changes the string being scanned to str and resets the scanner. Returns str.
Looks ahead to see if the pattern exists anywhere in the string, without advancing the scan pointer. This predicates whether a scan_until will return a value.
s = StringScanner.new('test string') s.exist? /s/ # -> 3 s.scan /test/ # -> "test" s.exist? /s/ # -> 2 s.exist? /e/ # -> nil
Sets the scan pointer to the previous position. Only one previous position is remembered, and it changes with each scanning operation.
s = StringScanner.new('test string') s.scan(/\w+/) # => "test" s.unscan s.scan(/../) # => "te" s.scan(/\d/) # => nil s.unscan # ScanError: unscan failed: previous match record not exist
Returns a string that represents the StringScanner object, showing:
the current position
the size of the string
the characters surrounding the scan pointer
s = StringScanner.new(“Fri Dec 12 1975 14:39”) s.inspect # -> ‘#<StringScanner 0/21 @ “Fri D…”>’ s.scan_until /12/ # -> “Fri Dec 12” s.inspect # -> ‘#<StringScanner 10/21 “…ec 12” @ “ 1975…”>’
Sets current codepage. The WIN32OLE.codepage is initialized according to Encoding.default_internal. If Encoding.default_internal is nil then WIN32OLE.codepage is initialized according to Encoding.default_external.
WIN32OLE.codepage = WIN32OLE::CP_UTF8 WIN32OLE.codepage = 65001
Returns a new String containing the hash entries:
h = {foo: 0, bar: 1, baz: 2} h.inspect # => "{:foo=>0, :bar=>1, :baz=>2}"
Hash#to_s is an alias for Hash#inspect.
Returns a copy of self with all nil-valued entries removed:
h = {foo: 0, bar: nil, baz: 2, bat: nil} h1 = h.compact h1 # => {:foo=>0, :baz=>2}
Returns self with all its nil-valued entries removed (in place):
h = {foo: 0, bar: nil, baz: 2, bat: nil} h.compact! # => {:foo=>0, :baz=>2}
Returns nil if no entries were removed.
Returns the contents of the environment as a String:
ENV.replace('foo' => '0', 'bar' => '1') ENV.inspect # => "{\"bar\"=>\"1\", \"foo\"=>\"0\"}"
Raises TypeError, because ENV is a wrapper for the process-wide environment variables and a clone is useless. Use to_h to get a copy of ENV data as a hash.
Returns “ARGF”.