Accept a connection on a socket
#include <sys/types.h> #include <sys/socket.h> int accept( int s, struct sockaddr * addr, socklen_t * addrlen );
The accept() function:
If no pending connections are present on the queue, and the socket isn't marked as nonblocking, accept() blocks the caller until a connection is present. If the socket is marked as nonblocking and no pending connections are present on the queue, accept() returns an error as described below. The accepted socket may not be used to accept more connections. The original socket s remains open.
If you do a select() for read on an unconnected socket (on which a listen() has been done), the select() indicates when a connect request has occurred. In this way, an accept() can be made that won't block. For more information, see select().
For certain protocols that require an explicit confirmation, accept() can be thought of as merely dequeuing the next connection request and not implying confirmation. Confirmation can be implied by a normal read or write on the new file descriptor, and rejection can be implied by closing the new socket.
You can obtain user-connection request data without confirming the connection by:
Or
Similarly, you can provide user-connection rejection information by issuing a sendmsg() call with only the control information, or by calling setsockopt().
A descriptor for the accepted socket, or -1 if an error occurs (errno is set).
Safety: | |
---|---|
Cancellation point | Yes |
Interrupt handler | No |
Signal handler | No |
Thread | Yes |