|SETSOCKOPT(3P)||POSIX Programmer's Manual||SETSOCKOPT(3P)|
int setsockopt(int socket, int level, int option_name, const void *option_value, socklen_t option_len);
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> 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.
- The socket argument is not a valid file descriptor.
- The send and receive timeout values are too big to fit into the timeout fields in the socket structure.
- 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:
- 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.
Options may exist at multiple protocol levels. The SO_ options are always present at the uppermost socket level.
The Base Definitions volume of POSIX.1‐2017, <netinet_in.h>, <sys_socket.h>
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 https://www.kernel.org/doc/man-pages/reporting_bugs.html .
|2017||IEEE/The Open Group|