libexplain/realpath.c File Reference

#include <libexplain/ac/errno.h>
#include <libexplain/ac/stdlib.h>
#include <libexplain/buffer/errno/realpath.h>
#include <libexplain/common_message_buffer.h>
#include <libexplain/realpath.h>

Go to the source code of this file.

Functions
const char *	explain_realpath (const char *pathname, char *resolved_pathname)
const char *	explain_errno_realpath (int errnum, const char *pathname, char *resolved_pathname)
void	explain_message_realpath (char *message, int message_size, const char *pathname, char *resolved_pathname)
void	explain_message_errno_realpath (char *message, int message_size, int errnum, const char *pathname, char *resolved_pathname)

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Function Documentation

const char* explain_errno_realpath	(	int	errnum,
		const char *	pathname,
		char *	resolved_pathname
	)

The explain_errno_realpath function is used to obtain an explanation of an error returned by the realpath(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.
pathname	The original pathname, exactly as passed to the realpath(3) system call.
resolved_pathname	The original resolved_pathname, exactly as passed to the realpath(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:

 char *result = realpath(pathname, resolved_pathname);
 if (!result)
 {
     int err = errno;
     fprintf(stderr, "%s\n", explain_errno_realpath(err, pathname,
         resolved_pathname));
     exit(EXIT_FAILURE);
 }

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

Definition at line 35 of file realpath.c.

void explain_message_errno_realpath	(	char *	message,
		int	message_size,
		int	errnum,
		const char *	pathname,
		char *	resolved_pathname
	)

The explain_message_errno_realpath function is used to obtain an explanation of an error returned by the realpath(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.
pathname	The original pathname, exactly as passed to the realpath(3) system call.
resolved_pathname	The original resolved_pathname, exactly as passed to the realpath(3) system call.

Example:

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

 char *result = realpath(pathname, resolved_pathname);
 if (!result)
 {
     int err = errno;
     char message[3000];
     explain_message_errno_realpath(message, sizeof(message), err, pathname,
         resolved_pathname);
     fprintf(stderr, "%s\n", message);
     exit(EXIT_FAILURE);
 }

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

Definition at line 55 of file realpath.c.

void explain_message_realpath	(	char *	message,
		int	message_size,
		const char *	pathname,
		char *	resolved_pathname
	)

The explain_message_realpath function is used to obtain an explanation of an error returned by the realpath(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.
pathname	The original pathname, exactly as passed to the realpath(3) system call.
resolved_pathname	The original resolved_pathname, exactly as passed to the realpath(3) system call.

Example:

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

 char *result = realpath(pathname, resolved_pathname);
 if (!result)
 {
     char message[3000];
     explain_message_realpath(message, sizeof(message), pathname,
         resolved_pathname);
     fprintf(stderr, "%s\n", message);
     exit(EXIT_FAILURE);
 }

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

Definition at line 46 of file realpath.c.

const char* explain_realpath	(	const char *	pathname,
		char *	resolved_pathname
	)

The explain_realpath function is used to obtain an explanation of an error returned by the realpath(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:

pathname	The original pathname, exactly as passed to the realpath(3) system call.
resolved_pathname	The original resolved_pathname, exactly as passed to the realpath(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:

 char *result = realpath(pathname, resolved_pathname);
 if (!result)
 {
     fprintf(stderr, "%s\n", explain_realpath(pathname, resolved_pathname));
     exit(EXIT_FAILURE);
 }

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

Definition at line 28 of file realpath.c.