#include <libexplain/ac/unistd.h>
#include <libexplain/buffer/errno/lseek.h>
#include <libexplain/lseek.h>

Functions
void	explain_message_errno_lseek (char *message, int message_size, int errnum, int fildes, off_t offset, int whence)

Function Documentation

void explain_message_errno_lseek	(	char *	message,
		int	message_size,
		int	errnum,
		int	fildes,
		off_t	offset,
		int	whence
	)

The explain_message_errno_lseek function is used to obtain an explanation of an error returned by the lseek(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.

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.
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 lseek(2) system call.
offset	The original offset, exactly as passed to the lseek(2) system call.
whence	The original whence, exactly as passed to the lseek(2) system call.

Example:

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

 off_t result = lseek(fildes, offset, whence);
 if (result < 0)
 {
     int err = errno;
     char message[3000];
     explain_message_errno_lseek(message, sizeof(message), err, fildes,
         offset, whence);
     fprintf(stderr, "%s\n", message);
     exit(EXIT_FAILURE);
 }

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

Definition at line 26 of file lseek.c.

Functions

Function Documentation