libexplain/access.c File Reference

#include <libexplain/ac/errno.h>
#include <libexplain/access.h>
#include <libexplain/buffer/errno/access.h>
#include <libexplain/common_message_buffer.h>
#include <libexplain/string_buffer.h>

Go to the source code of this file.

Functions
const char *	explain_access (const char *pathname, int mode)
const char *	explain_errno_access (int errnum, const char *pathname, int mode)
void	explain_message_access (char *message, int message_size, const char *pathname, int mode)
void	explain_message_errno_access (char *message, int message_size, int errnum, const char *pathname, int mode)

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Function Documentation

const char* explain_access	(	const char *	pathname,
		int	mode
	)

The explain_access function is used to obtain an explanation of an error returned by the access(2) 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.

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

 if (access(pathname, mode) < 0)
 {
     fprintf(stderr, "%s\n", explain_access(pathname, mode));
     exit(EXIT_FAILURE);
 }

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

Parameters:

pathname	The original pathname, exactly as passed to the access(2) system call.
mode	The original mode, exactly as passed to the access(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 29 of file access.c.

const char* explain_errno_access	(	int	errnum,
		const char *	pathname,
		int	mode
	)

The explain_errno_access function is used to obtain an explanation of an error returned by the access(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 (access(pathname, mode) < 0)
 {
     int err = errno;
     fprintf(stderr, "%s\n", explain_access(err, pathname, mode));
     exit(EXIT_FAILURE);
 }

The above code example is available pre-packaged as the explain_access_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.
pathname	The original pathname, exactly as passed to the access(2) system call.
mode	The original mode, exactly as passed to the access(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 36 of file access.c.

void explain_message_access	(	char *	message,
		int	message_size,
		const char *	pathname,
		int	mode
	)

The explain_message_access function is used to obtain an explanation of an error returned by the access(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 (access(pathname, mode) < 0)
 {
     char message[3000];
     explain_message_access(message, sizeof(message), pathname, mode);
     fprintf(stderr, "%s\n", message);
     exit(EXIT_FAILURE);
 }

The above code example is available pre-packaged as the explain_access_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.
pathname	The original pathname, exactly as passed to the access(2) system call.
mode	The original mode, exactly as passed to the access(2) system call.

Definition at line 51 of file access.c.

void explain_message_errno_access	(	char *	message,
		int	message_size,
		int	errnum,
		const char *	pathname,
		int	mode
	)

The explain_message_errno_access function is used to obtain an explanation of an error returned by the access(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 (access(pathname, mode) < 0)
 {
     int err = errno;
     char message[3000];
     explain_message_errno_access(message, sizeof(message), err, pathname,
         mode);
     fprintf(stderr, "%s\n", message);
     exit(EXIT_FAILURE);
 }

The above code example is available pre-packaged as the explain_access_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.
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 access(2) system call.
mode	The original mode, exactly as passed to the access(2) system call.

Definition at line 66 of file access.c.