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The primitive for creating a socket is the socket
function,
declared in sys/socket.h.
Preliminary: | MT-Safe | AS-Safe | AC-Safe fd | See POSIX Safety Concepts.
This function creates a socket and specifies communication style
style, which should be one of the socket styles listed in
Communication Styles. The namespace argument specifies
the namespace; it must be PF_LOCAL
(see Local Namespace) or
PF_INET
(see Internet Namespace). protocol
designates the specific protocol (see Socket Concepts); zero is
usually right for protocol.
The return value from socket
is the file descriptor for the new
socket, or -1
in case of error. The following errno
error
conditions are defined for this function:
EPROTONOSUPPORT
The protocol or style is not supported by the namespace specified.
EMFILE
The process already has too many file descriptors open.
ENFILE
The system already has too many file descriptors open.
EACCES
The process does not have the privilege to create a socket of the specified style or protocol.
ENOBUFS
The system ran out of internal buffer space.
The file descriptor returned by the socket
function supports both
read and write operations. However, like pipes, sockets do not support file
positioning operations.
For examples of how to call the socket
function,
see Local Socket Example, or Inet Example.