long int ftell(FILE *stream
Returns the current file position of the given stream. If it is a binary stream, then the value is the number of bytes from the beginning of the file. If it is a text stream, then the value is a value useable by the fseek function to return the file position to the current position.
On success the current file position is returned. On error a value of
-1L is returned and
errno is set.