#include <libexplain/access.h>
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);
DESCRIPTION
These functions may be used to obtain explanations
for access(2) errors.
explain_access
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:
int fd = access(pathname, mode);
if (fd < 0)
{
fprintf(stderr, "%s, explain_access(pathname, mode));
exit(EXIT_FAILURE);
}
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.
TP 8n
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_access
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:
int fd = access(pathname, mode);
if (fd < 0)
{
int err = errno;
fprintf(stderr, "%s, explain_errno_access(err, pathname,
mode));
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.
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.
explain_message_access
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(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:
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.
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.
explain_message_errno_access
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 exameple:
int fd = access(pathname, mode);
if (fd < 0)
{
int err = errno;
char message[3000];
explain_message_errno_access(message, sizeof(message), err,
pathname, mode);
fprintf(stderr, "%s, 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.
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.
COPYRIGHT
libexplain version 0.37
Copyright (C) 2008 Peter Miller