libexplain/errno/setsockopt.c File Reference

#include <libexplain/ac/sys/socket.h>
#include <libexplain/common_message_buffer.h>
#include <libexplain/setsockopt.h>

Go to the source code of this file.

Functions
const char *	explain_errno_setsockopt (int errnum, int fildes, int level, int name, void *data, socklen_t data_size)

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Function Documentation

const char* explain_errno_setsockopt	(	int	errnum,
		int	fildes,
		int	level,
		int	name,
		void *	data,
		socklen_t	data_size
	)

The explain_errno_setsockopt function is used to obtain an explanation of an error returned by the setsockopt(2) system call. The least the message will contain is the value of strerror(errnum), but usually it will do much better, and indicate the underlying cause in more detail.

This function is intended to be used in a fashion similar to the following example:

 if (setsockopt(fildes, level, name, data, data_size) < 0)
 {
     int err = errno;
     fprintf(stderr, "%s\n", explain_errno_setsockopt(err, fildes, level,
         name, data, data_size));
     exit(EXIT_FAILURE);
 }

The above code example is available pre-packaged as the explain_setsockopt_or_die function.

Parameters:

errnum	The error value to be decoded, usually obtained from the errno global variable just before this function is called. This is necessary if you need to call any code between the system call to be explained and this function, because many libc functions will alter the value of errno.
fildes	The original fildes, exactly as passed to the setsockopt(2) system call.
level	The original level, exactly as passed to the setsockopt(2) system call.
name	The original name, exactly as passed to the setsockopt(2) system call.
data	The original data, exactly as passed to the setsockopt(2) system call.
data_size	The original data_size, exactly as passed to the setsockopt(2) system call.

Returns:

The message explaining the error. This message buffer is shared by all libexplain functions which do not supply a buffer in their argument list. This will be overwritten by the next call to any libexplain function which shares this buffer, including other threads.

Note:

This function is not thread safe, because it shares a return buffer across all threads, and many other functions in this library.

Definition at line 26 of file setsockopt.c.