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If applicable, add the following below this CDDL HEADER, with the fields enclosed by brackets "[]" replaced with your own identifying information: Portions Copyright [yyyy] [name of copyright owner] .TH ACCEPT 3SOCKET "Apr 19, 2013" .SH NAME accept \- accept a connection on a socket .SH SYNOPSIS .LP .nf \fBcc\fR [ \fIflag\fR ... ] \fIfile\fR ... \fB-lsocket\fR \fB -lnsl \fR [ \fIlibrary\fR ... ] #include #include \fBint\fR \fBaccept\fR(\fBint\fR \fIs\fR, \fBstruct sockaddr *\fR\fIaddr\fR, \fBsocklen_t *\fR\fIaddrlen\fR); \fBint\fR \fBaccept4\fR(\fBint\fR \fIs\fR, \fBstruct sockaddr *\fR\fIaddr\fR, \fBsocklen_t *\fR\fIaddrlen\fR, \fBint\fR \fIflags\fR); .fi .SH DESCRIPTION .LP The argument \fIs\fR is a socket that has been created with \fBsocket\fR(3SOCKET) and bound to an address with \fBbind\fR(3SOCKET), and that is listening for connections after a call to \fBlisten\fR(3SOCKET). The \fBaccept()\fR function extracts the first connection on the queue of pending connections, creates a new socket with the properties of \fIs\fR, and allocates a new file descriptor, \fIns\fR, for the socket. If no pending connections are present on the queue and the socket is not marked as non-blocking, \fBaccept()\fR blocks the caller until a connection is present. If the socket is marked as non-blocking and no pending connections are present on the queue, \fBaccept()\fR returns an error as described below. The \fBaccept()\fR function uses the \fBnetconfig\fR(5) file to determine the \fBSTREAMS\fR device file name associated with \fIs\fR. This is the device on which the connect indication will be accepted. The accepted socket, \fIns\fR, is used to read and write data to and from the socket that connected to \fIns\fR. It is not used to accept more connections. The original socket (\fIs\fR) remains open for accepting further connections. .sp .LP The argument \fIaddr\fR is a result parameter that is filled in with the address of the connecting entity as it is known to the communications layer. The exact format of the \fIaddr\fR parameter is determined by the domain in which the communication occurs. .sp .LP The argument \fIaddrlen\fR is a value-result parameter. Initially, it contains the amount of space pointed to by \fIaddr\fR; on return it contains the length in bytes of the address returned. .sp .LP The \fBaccept()\fR function is used with connection-based socket types, currently with \fBSOCK_STREAM\fR. .sp .LP The \fBaccept4()\fR function allows flags that control the behavior of a successfully accepted socket. If \fIflags\fR is 0, \fBaccept4()\fR acts identically to \fBaccept()\fR. Values for \fIflags\fR are constructed by a bitwise-inclusive-OR of flags from the following list, defined in . .sp .ne 2 .na \fB\fBSOCK_CLOEXEC\fR\fR .ad .RS 12n The accepted socket will have the FD_CLOEXEC flag set as if \fBfcntl()\fR was called on it. This flag is set before the socket is passed to the caller thus avoiding the race condition between \fBaccept()\fR and \fBfcntl()\fR. See, \fBO_CLOEXEC\fR in \fBopen(2)\fR for more details. .RE .sp .ne 2 .na \fB\fBSOCK_NDELAY\fR\fR .ad .RS 12n The accepted socket will have the \fBO_NDELAY\fR flag set as if \fBfcntl()\fR was called on it. This sets the socket into non-blocking mode. See \fBO_NDELAY\fR in \fBfcntl.h(3HEAD)\fR for more details. .RE .sp .ne 2 .na \fB\fBSOCK_NONBLOCK\fR\fR .ad .RS 12n The accepted socket will have the \fBO_NONBLOCK\fR flag set as if \fBfcntl()\fR was called on it. This sets the socket into non-blocking mode (POSIX; see \fBstandards\fR(7)). See \fBO_NONBLOCK\fR in \fBfcntl.h(3HEAD)\fR for more details. .RE .sp .LP It is possible to \fBselect\fR(3C) or \fBpoll\fR(2) a socket for the purpose of an \fBaccept()\fR by selecting or polling it for a read. However, this will only indicate when a connect indication is pending; it is still necessary to call \fBaccept()\fR. .SH RETURN VALUES .LP The \fBaccept()\fR function returns \fB\(mi1\fR on error. If it succeeds, it returns a non-negative integer that is a descriptor for the accepted socket. .SH ERRORS .LP \fBaccept()\fR and \fBaccept4()\fR will fail if: .sp .ne 2 .na \fB\fBEBADF\fR\fR .ad .RS 16n The descriptor is invalid. .RE .sp .ne 2 .na \fB\fBECONNABORTED\fR\fR .ad .RS 16n The remote side aborted the connection before the \fBaccept()\fR operation completed. .RE .sp .ne 2 .na \fB\fBEFAULT\fR\fR .ad .RS 16n The \fIaddr\fR parameter or the \fIaddrlen\fR parameter is invalid. .RE .sp .ne 2 .na \fB\fBEINTR\fR\fR .ad .RS 16n The \fBaccept()\fR attempt was interrupted by the delivery of a signal. .RE .sp .ne 2 .na \fB\fBEMFILE\fR\fR .ad .RS 16n The per-process descriptor table is full. .RE .sp .ne 2 .na \fB\fBENODEV\fR\fR .ad .RS 16n The protocol family and type corresponding to \fIs\fR could not be found in the \fBnetconfig\fR file. .RE .sp .ne 2 .na \fB\fBENOMEM\fR\fR .ad .RS 16n There was insufficient user memory available to complete the operation. .RE .sp .ne 2 .na \fB\fBENOSR\fR\fR .ad .RS 16n There were insufficient \fBSTREAMS\fR resources available to complete the operation. .RE .sp .ne 2 .na \fB\fBENOTSOCK\fR\fR .ad .RS 16n The descriptor does not reference a socket. .RE .sp .ne 2 .na \fB\fBEOPNOTSUPP\fR\fR .ad .RS 16n The referenced socket is not of type \fBSOCK_STREAM\fR. .RE .sp .ne 2 .na \fB\fBEPROTO\fR\fR .ad .RS 16n A protocol error has occurred; for example, the \fBSTREAMS\fR protocol stack has not been initialized or the connection has already been released. .RE .sp .ne 2 .na \fB\fBEWOULDBLOCK\fR\fR .ad .RS 16n The socket is marked as non-blocking and no connections are present to be accepted. .RE .sp .LP Additionally, \fBaccept4()\fR will fail if: .sp .ne 2 .na \fB\fBEINVAL\fR\fR .ad .RS 16n The \fIflags\fR value is invalid. The \fIflags\fR argument can only be the bitwise inclusive-OR of \fBSOCK_CLOEXEC\fR, \fBSOCK_NONBLOCK\fR, and \fBSOCK_NDELAY\fR. .RE .SH ATTRIBUTES .LP See \fBattributes\fR(7) for descriptions of the following attributes: .sp .sp .TS box; c | c l | l . ATTRIBUTE TYPE ATTRIBUTE VALUE _ MT-Level Safe .TE .SH SEE ALSO .LP \fBpoll\fR(2), \fBbind\fR(3SOCKET), \fBconnect\fR(3SOCKET), \fBlisten\fR(3SOCKET), \fBsockaddr\fR(3SOCKET), \fBselect\fR(3C), \fBsocket.h\fR(3HEAD), \fBsocket\fR(3SOCKET), \fBnetconfig\fR(5), \fBattributes\fR(7), \fBfcntl.h(3HEAD)\fR, \fBfcntl(2)\fR, \fBstandards\fR(7)