#include <libexplain/ac/errno.h>
#include <libexplain/ac/stdio.h>
#include <libexplain/buffer/errno/fseek.h>
#include <libexplain/common_message_buffer.h>
#include <libexplain/fseek.h>

Functions
const char *	explain_fseek (FILE *fp, long offset, int whence)
const char *	explain_errno_fseek (int errnum, FILE *fp, long offset, int whence)
void	explain_message_fseek (char message, int message_size, FILE fp, long offset, int whence)
void	explain_message_errno_fseek (char message, int message_size, int errnum, FILE fp, long offset, int whence)

Function Documentation

const char* explain_errno_fseek	(	int	errnum,
		FILE *	fp,
		long	offset,
		int	whence
	)

The explain_errno_fseek function is used to obtain an explanation of an error returned by the fseek(3) 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:

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.
fp	The original fp, exactly as passed to the fseek(3) system call.
offset	The original offset, exactly as passed to the fseek(3) system call.
whence	The original whence, exactly as passed to the fseek(3) 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.

Example:

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

 if (fseek(fp, offset, whence) < 0)
 {
     int err = errno;
     fprintf(stderr, "%s\n", explain_errno_fseek(err, fp, offset, whence));
     exit(EXIT_FAILURE);
 }

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

Definition at line 35 of file fseek.c.

const char* explain_fseek	(	FILE *	fp,
		long	offset,
		int	whence
	)

The explain_fseek function is used to obtain an explanation of an error returned by the fseek(3) system call. The least the message will contain is the value of strerror(errno), 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.

Parameters:

fp	The original fp, exactly as passed to the fseek(3) system call.
offset	The original offset, exactly as passed to the fseek(3) system call.
whence	The original whence, exactly as passed to the fseek(3) 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.

Example:

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

 if (fseek(fp, offset, whence) < 0)
 {
     fprintf(stderr, "%s\n", explain_fseek(fp, offset, whence));
     exit(EXIT_FAILURE);
 }

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

Definition at line 28 of file fseek.c.

void explain_message_errno_fseek	(	char *	message,
		int	message_size,
		int	errnum,
		FILE *	fp,
		long	offset,
		int	whence
	)

The explain_message_errno_fseek function is used to obtain an explanation of an error returned by the fseek(3) 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.
fp	The original fp, exactly as passed to the fseek(3) system call.
offset	The original offset, exactly as passed to the fseek(3) system call.
whence	The original whence, exactly as passed to the fseek(3) system call.

Example:

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

 if (fseek(fp, offset, whence) < 0)
 {
     int err = errno;
     char message[3000];
     explain_message_errno_fseek(message, sizeof(message), err, fp, offset,
         whence);
     fprintf(stderr, "%s\n", message);
     exit(EXIT_FAILURE);
 }

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

Definition at line 53 of file fseek.c.

void explain_message_fseek	(	char *	message,
		int	message_size,
		FILE *	fp,
		long	offset,
		int	whence
	)

The explain_message_fseek function is used to obtain an explanation of an error returned by the fseek(3) 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.

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.
fp	The original fp, exactly as passed to the fseek(3) system call.
offset	The original offset, exactly as passed to the fseek(3) system call.
whence	The original whence, exactly as passed to the fseek(3) system call.

Example:

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

 if (fseek(fp, offset, whence) < 0)
 {
     char message[3000];
     explain_message_fseek(message, sizeof(message), fp, offset, whence);
     fprintf(stderr, "%s\n", message);
     exit(EXIT_FAILURE);
 }

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

Definition at line 44 of file fseek.c.

Functions

Function Documentation