setsockopt(3p) — Linux manual page


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

RETURN VALUE         top

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

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 complete.

              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.1‐2017, netinet_in.h(0p),

COPYRIGHT         top

       Portions of this text are reprinted and reproduced in electronic
       form from IEEE Std 1003.1-2017, Standard for Information
       Technology -- Portable Operating System Interface (POSIX), The
       Open Group Base Specifications Issue 7, 2018 Edition, Copyright
       (C) 2018 by the Institute of Electrical and Electronics
       Engineers, Inc and The Open Group.  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               2017                    SETSOCKOPT(3P)

Pages that refer to this page: netinet_in.h(0p)netinet_tcp.h(0p)sys_socket.h(0p)getsockopt(3p)if_freenameindex(3p)if_indextoname(3p)if_nameindex(3p)if_nametoindex(3p)send(3p)sendmsg(3p)sendto(3p)shutdown(3p)socket(3p)