Provided by: explain_0.52.D002-1_amd64 
NAME
explain_fopen - explain fopen(3) errors
SYNOPSIS
#include <libexplain/fopen.h>
const char *explain_fopen(const char *path, const char *mode);
const char *explain_errno_fopen(int errnum, const char *path, const char *mode);
void explain_message_fopen(char *message, int message_size, const char *path, const char *mode);
void explain_message_errno_fopen(char *message, int message_size, int errnum, const char *path, const
char *mode);
DESCRIPTION
These functions may be used to obtain explanations for fopen(3) errors.
explain_fopen
const char *explain_fopen(const char *path, const char *mode);
The explain_fopen function is used to obtain an explanation of an error returned by the fopen(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.
This function is intended to be used in a fashion similar to the following example:
FILE *fp = fopen(path, mode);
if (!fp)
{
const char *message = explain_fopen(path, mode);
fprintf(stderr, '%s0, message);
exit(EXIT_FAILURE);
}
path The original path, exactly as passed to the fopen(3) system call.
mode The original mode, exactly as passed to the fopen(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.
explain_errno_fopen
const char *explain_errno_fopen(int errnum, const char *path, const char *mode);
The explain_errno_fopen function is used to obtain an explanation of an error returned by the fopen(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.
This function is intended to be used in a fashion similar to the following example:
FILE *fp = fopen(path, mode);
if (!fp)
{
const char *message = explain_errno_fopen(err, path, mode);
fprintf(stderr, '%s0, message);
exit(EXIT_FAILURE);
}
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.
path The original path, exactly as passed to the fopen(3) system call.
mode The original mode, exactly as passed to the fopen(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.
explain_message_fopen
void explain_message_fopen(char *message, int message_size, const char *path, const char *mode);
The explain_message_fopen function is used to obtain an explanation of an error returned by the fopen(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.
This function is intended to be used in a fashion similar to the following example:
FILE *fp = fopen(path, mode);
if (!fp)
{
char message[3000];
explain_message_fopen(message, sizeof(message), path, mode);
fprintf(stderr, '%s0, message);
exit(EXIT_FAILURE);
}
message The location in which to store the returned message. Because a message return buffer has been
supplied, this function is thread safe.
message_size
The size in bytes of the location in which to store the returned message.
path The original path, exactly as passed to the fopen(3) system call.
mode The original mode, exactly as passed to the fopen(3) system call
explain_message_errno_fopen
void explain_message_errno_fopen(char *message, int message_size, int errnum, const char *path, const
char *mode);
The explain_message_errno_fopen function is used to obtain an explanation of an error returned by the
fopen(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.
This function is intended to be used in a fashion similar to the following example:
FILE *fp = fopen(path, mode);
if (!fp)
{
int err = errno;
char message[3000];
explain_message_errno_fopen(message, sizeof(message), err, path,
mode);
fprintf(stderr, '%s0, message);
exit(EXIT_FAILURE);
}
message The location in which to store the returned message. Because a message return buffer has been
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.
path The original path, exactly as passed to the fopen(3) system call.
mode The original mode, exactly as passed to the fopen(3) system call.
COPYRIGHT
libexplain version 0.52
Copyright (C) 2008 Peter Miller
AUTHOR
Written by Peter Miller <pmiller@opensource.org.au>
explain_fopen(3)