bool al_fseek(ALLEGRO_FILE *f, int64_t offset, int whence)
Set the current position of the given file to a position relative to that specified by 'whence', plus 'offset' number of bytes.
'whence' can be:
- ALLEGRO_SEEK_SET - seek relative to beginning of file
- ALLEGRO_SEEK_CUR - seek relative to current file position
- ALLEGRO_SEEK_END - seek relative to end of file
Returns true on success, false on failure. errno is set to indicate the error.
After a successful seek, the end-of-file indicator is cleared and all pushback bytes are forgotten.
On some platforms this function may not support large files.