int explain_filename_from_fildes(int fildes, char *data, size_t data_size);
int explain_filename_from_stream(FILE *stream, char *data, size_t data_size);
The I]explain_filename_from_fildes function may be used to
obtain the name of the file associated with the file descriptor.
The I]explain_filename_from_stream function may be used to
obtain the name of the file associated with a file stream.
The filename is returned in the array pointed to by I]data.
The filename will always be NUL terminated.
If the returned filename is longer than I]data_size, it will be silently
truncated; a size of at least (PATH_MAX + 1) is suggested.
On success, returns zero.
If the file name cannot be determined, returns -1 (but does B]not