www.delorie.com/gnu/docs/glibc/libc_351.html   search  
 
Buy the book!


The GNU C Library

[ < ] [ > ]   [ << ] [ Up ] [ >> ]         [Top] [Contents] [Index] [ ? ]

16.12.1 Socket Option Functions

Here are the functions for examining and modifying socket options. They are declared in `sys/socket.h'.

Function: int getsockopt (int socket, int level, int optname, void *optval, socklen_t *optlen-ptr)
The getsockopt function gets information about the value of option optname at level level for socket socket.

The option value is stored in a buffer that optval points to. Before the call, you should supply in *optlen-ptr the size of this buffer; on return, it contains the number of bytes of information actually stored in the buffer.

Most options interpret the optval buffer as a single int value.

The actual return value of getsockopt is 0 on success and -1 on failure. The following errno error conditions are defined:

EBADF
The socket argument is not a valid file descriptor.

ENOTSOCK
The descriptor socket is not a socket.

ENOPROTOOPT
The optname doesn't make sense for the given level.

Function: int setsockopt (int socket, int level, int optname, void *optval, socklen_t optlen)
This function is used to set the socket option optname at level level for socket socket. The value of the option is passed in the buffer optval of size optlen.

The return value and error codes for setsockopt are the same as for getsockopt.


  webmaster     delorie software   privacy  
  Copyright 2003   by The Free Software Foundation     Updated Jun 2003