ACCEPT(2) UNIX Programmer's Manual ACCEPT(2) NAME accept - accept a connection on a socket SYNOPSIS #include #include ns = accept(s, addr, addrlen) int ns, s; struct sockaddr *addr; int *addrlen; DESCRIPTION The argument _s is a socket that has been created with _s_o_c_k_e_t(2), bound to an address with _b_i_n_d(2), and is listen- ing for connections after a _l_i_s_t_e_n(2). _A_c_c_e_p_t extracts the first connection on the queue of pending connections, creates a new socket with the same properties of _s and allo- cates a new file descriptor, _n_s, for the socket. If no pending connections are present on the queue, and the socket is not marked as non-blocking, _a_c_c_e_p_t blocks the caller until a connection is present. If the socket is marked non-blocking and no pending connections are present on the queue, _a_c_c_e_p_t returns an error as described below. The accepted socket, _n_s, may not be used to accept more connec- tions. The original socket _s remains open. The argument _a_d_d_r 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 _a_d_d_r parame- ter is determined by the domain in which the communication is occurring. The _a_d_d_r_l_e_n is a value-result parameter; it should initially contain the amount of space pointed to by _a_d_d_r; on return it will contain the actual length (in bytes) of the address returned. This call is used with connection-based socket types, currently with SOCK_STREAM. It is possible to _s_e_l_e_c_t(2) a socket for the purposes of doing an _a_c_c_e_p_t by selecting it for read. RETURN VALUE The call returns -1 on error. If it succeeds, it returns a non-negative integer that is a descriptor for the accepted socket. ERRORS The _a_c_c_e_p_t will fail if: [EBADF] The descriptor is invalid. [ENOTSOCK] The descriptor references a file, not a socket. Printed 11/26/99 May 22, 1986 1 ACCEPT(2) UNIX Programmer's Manual ACCEPT(2) [EOPNOTSUPP] The referenced socket is not of type SOCK_STREAM. [EFAULT] The _a_d_d_r parameter is not in a writable part of the user address space. [EWOULDBLOCK] The socket is marked non-blocking and no connections are present to be accepted. SEE ALSO bind(2), connect(2), listen(2), select(2), socket(2) Printed 11/26/99 May 22, 1986 2