ultrix man page for accept

accept(2)							System Calls Manual							 accept(2)

Name
       accept - accept a connection on a socket

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

       accept(s, addr, addrlen)
       int ns, s;
       struct sockaddr *addr;
       int *addrlen;

Description
       The  system call accepts a connection on a socket. The argument s is a socket that has been created with the call, bound to an address with
       the call and is listening for connections after a call.	The system call extracts the first connection on the queue of pending connections,
       creates	a new socket with the same properties of s and allocates a new file descriptor, ns, for the socket.  If no pending connections are
       present on the queue, and the socket is not marked as nonblocking, blocks the caller until a connection	is  present.   If  the	socket	is
       marked  nonblocking  and  no  pending  connections  are present on the queue, returns an error.	The accepted socket, ns, cannot be used to
       accept more connections.  The original socket s remains open.

       The argument addr is a result parameter that is filled in with the address of the connecting entity, as known to the communications  layer.
       The  exact format of the addr parameter is determined by the domain in which the communication is occurring.  The addrlen is a value-result
       parameter; it should initially contain the amount of space pointed to by addr.  On return, addr contains the actual length in bytes of  the
       address returned.  This call is used with connection-based socket types, currently with SOCK_STREAM.

       You can use the call for the purposes of doing an call by selecting the socket for reading.

Return Values
       The call returns -1 on error.  If the call succeeds, it returns a non-negative integer which is a descriptor for the accepted socket.

Diagnostics
       The call fails if:

       [EBADF]	      The descriptor is invalid.

       [ENOTSOCK]     The descriptor references a file, not a socket.

       [EOPNOTSUPP]   The referenced socket is not of type SOCK_STREAM.

       [EFAULT]       The addr parameter is not in a writable part of the user address space.

       [EWOULDBLOCK]  The socket is marked nonblocking and no connections are present to be accepted.

See Also
       bind(2), connect(2), listen(2), select(2), socket(2)

																	 accept(2)