libexplain/message/fcntl.c File Reference

#include <libexplain/ac/errno.h>
#include <libexplain/fcntl.h>

Go to the source code of this file.

Functions
void	explain_message_fcntl (char *message, int message_size, int fildes, int command, long arg)

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Function Documentation

void explain_message_fcntl	(	char *	message,
		int	message_size,
		int	fildes,
		int	command,
		long	arg
	)

The explain_message_fcntl function is used to obtain an explanation of an error returned by the fcntl(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.

The errno global variable will be used to obtain the error value to be decoded.

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

 if (fcntl(fildes, command, arg) < 0)
 {
     char message[3000];
     explain_message_fcntl(message, sizeof(message), fildes, command, arg);
     fprintf(stderr, "%s\n", message);
     exit(EXIT_FAILURE);
 }

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

Parameters:

message	The location in which to store the returned message. If a suitable message return buffer is supplied, this function is thread safe.
message_size	The size in bytes of the location in which to store the returned message.
fildes	The original fildes, exactly as passed to the fcntl(2) system call.
command	The original command, exactly as passed to the fcntl(2) system call.
arg	The original arg, exactly as passed to the fcntl(2) system call.

Definition at line 26 of file fcntl.c.