SOCKETPAIR(2) System Calls Manual SOCKETPAIR(2)

socketpair — create a pair of connected sockets

#include <sys/socket.h>

int
socketpair(int domain, int type, int protocol, int socket_vector[2]);

The () call creates an unnamed pair of connected sockets in the specified domain domain, of the specified type, and using the optionally specified protocol. The descriptors used in referencing the new sockets are returned in socket_vector[0] and socket_vector[1]. The two sockets are indistinguishable.

The socketpair() function returns the value 0 if successful; otherwise the value -1 is returned and the global variable errno is set to indicate the error.

The call succeeds unless:

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The specified address family is not supported on this machine.
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The address socket_vector does not specify a valid part of the process address space.
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No more file descriptors are available for this process.
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No more file descriptors are available for the system.
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Insufficient resources were available in the system to perform the operation.
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Insufficient memory was available to fulfill the request.
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The specified protocol does not support creation of socket pairs.
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The specified protocol is not supported on this machine.
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The socket type is not supported by the protocol.
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The process does not have appropriate privileges to create a socket of the specified type and/or protocol.

#include <sys/types.h> #include <sys/socket.h>

The include file <sys/types.h> is necessary.

socket(2), read(2), write(2), compat(5)

This call is currently implemented only for the UNIX domain.

The socketpair() function call appeared in 4.2BSD.

June 4, 1993 BSD 4.2