SETSOCKOPT(3P)            POSIX Programmer's Manual           SETSOCKOPT(3P)

PROLOG         top

       This manual page is part of the POSIX Programmer's Manual.  The Linux
       implementation of this interface may differ (consult the
       corresponding Linux manual page for details of Linux behavior), or
       the interface may not be implemented on Linux.

NAME         top

       setsockopt — set the socket options

SYNOPSIS         top

       #include <sys/socket.h>

       int setsockopt(int socket, int level, int option_name,
           const void *option_value, socklen_t option_len);

DESCRIPTION         top

       The setsockopt() function shall set the option specified by the
       option_name argument, at the protocol level specified by the level
       argument, to the value pointed to by the option_value argument for
       the socket associated with the file descriptor specified by the
       socket argument.

       The level argument specifies the protocol level at which the option
       resides. To set options at the socket level, specify the level
       argument as SOL_SOCKET. To set options at other levels, supply the
       appropriate level identifier for the protocol controlling the option.
       For example, to indicate that an option is interpreted by the TCP
       (Transport Control Protocol), set level to IPPROTO_TCP as defined in
       the <netinet/in.h> header.

       The option_name argument specifies a single option to set. It can be
       one of the socket-level options defined in sys_socket.h(0p) and
       described in Section 2.10.16, Use of Options.  If option_name is
       equal to SO_RCVTIMEO or SO_SNDTIMEO and the implementation supports
       setting the option, it is unspecified whether the struct timeval
       pointed to by option_value is stored as provided by this function or
       is rounded up to align with the resolution of the clock being used.
       If setsockopt() is called with option_name equal to SO_ACCEPTCONN,
       SO_ERROR, or SO_TYPE, the behavior is unspecified.

RETURN VALUE         top

       Upon successful completion, setsockopt() shall return 0. Otherwise,
       −1 shall be returned and errno set to indicate the error.

ERRORS         top

       The setsockopt() function shall fail if:

       EBADF  The socket argument is not a valid file descriptor.

       EDOM   The send and receive timeout values are too big to fit into
              the timeout fields in the socket structure.

       EINVAL The specified option is invalid at the specified socket level
              or the socket has been shut down.

              The socket is already connected, and a specified option cannot
              be set while the socket is connected.

              The option is not supported by the protocol.

              The socket argument does not refer to a socket.

       The setsockopt() function may fail if:

       ENOMEM There was insufficient memory available for the operation to

              Insufficient resources are available in the system to complete
              the call.

       The following sections are informative.

EXAMPLES         top



       The setsockopt() function provides an application program with the
       means to control socket behavior. An application program can use
       setsockopt() to allocate buffer space, control timeouts, or permit
       socket data broadcasts. The <sys/socket.h> header defines the socket-
       level options available to setsockopt().

       Options may exist at multiple protocol levels. The SO_ options are
       always present at the uppermost socket level.

RATIONALE         top




SEE ALSO         top

       Section 2.10, Sockets, bind(3p), endprotoent(3p), getsockopt(3p),

       The Base Definitions volume of POSIX.1‐2008, netinet_in.h(0p),

COPYRIGHT         top

       Portions of this text are reprinted and reproduced in electronic form
       from IEEE Std 1003.1, 2013 Edition, Standard for Information
       Technology -- Portable Operating System Interface (POSIX), The Open
       Group Base Specifications Issue 7, Copyright (C) 2013 by the
       Institute of Electrical and Electronics Engineers, Inc and The Open
       Group.  (This is POSIX.1-2008 with the 2013 Technical Corrigendum 1
       applied.) In the event of any discrepancy between this version and
       the original IEEE and The Open Group Standard, the original IEEE and
       The Open Group Standard is the referee document. The original
       Standard can be obtained online at .

       Any typographical or formatting errors that appear in this page are
       most likely to have been introduced during the conversion of the
       source files to man page format. To report such errors, see .

IEEE/The Open Group                 2013                      SETSOCKOPT(3P)