The explain_sprintf function is used to obtain an explanation of an
error returned by the sprintf(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.
data
The original data, exactly as passed to the sprintf(3) system call.
format
The original format, exactly as passed to the sprintf(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:
errno = EINVAL;
int result = sprintf(data, format, ...);
if (result < 0)
{
fprintf(stderr, "%s\n", explain_sprintf(data, format, ...));
exit(EXIT_FAILURE);
}
The above code example is available pre-packaged as the
explain_sprintf_or_die(3) function.
The explain_errno_sprintf function is used to obtain an explanation
of an error returned by the sprintf(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.
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.
data
The original data, exactly as passed to the sprintf(3) system call.
format
The original format, exactly as passed to the sprintf(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:
errno = EINVAL;
int result = sprintf(data, format, ...);
if (result < 0)
{
int err = errno;
fprintf(stderr, "%s\n", explain_errno_sprintf(err, data, format, ...));
exit(EXIT_FAILURE);
}
The above code example is available pre-packaged as the
explain_sprintf_or_die(3) function.
The explain_message_sprintf function is used to obtain an
explanation of an error returned by the sprintf(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.
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.
data
The original data, exactly as passed to the sprintf(3) system call.
format
The original format, exactly as passed to the sprintf(3) system
call.
Example: This function is intended to be used in a fashion similar
to the following example:
errno = EINVAL;
int result = sprintf(data, format, ...);
if (result < 0)
{
char message[3000];
explain_message_sprintf(message, sizeof(message), data, format, ...);
The above code example is available pre-packaged as the
explain_sprintf_or_die(3) function.
explain_message_errno_sprintf
void explain_message_errno_sprintf(char *message, int message_size, int
errnum, char *data, const char *format, ...);
The explain_message_errno_sprintf function is used to obtain an
explanation of an error returned by the sprintf(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.
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.
data
The original data, exactly as passed to the sprintf(3) system call.
format
The original format, exactly as passed to the sprintf(3) system
call.
Example: This function is intended to be used in a fashion similar
to the following example:
errno = EINVAL;
int result = sprintf(data, format, ...);
if (result < 0)
{
int err = errno;
char message[3000];
explain_message_errno_sprintf(message, sizeof(message), err, data, format, ...);