C Programming/C Reference/stdio.h/ftell
The function ftell returns the current offset in a stream in relation to the first byte. It returns the current file position for stream, or -1 if an error occurs.
long ftell ( FILE * stream );
The function ftell returns the current offset in a stream in relation to the first byte. It returns the current file position for stream, or -1 if an error occurs.
long ftell ( FILE * stream );