pack_fclose_chunk man page
pack_fclose_chunk — Closes a previously opened sub-chunk. Allegro game programming library.
PACKFILE *pack_fclose_chunk(PACKFILE *f);
Closes a sub-chunk of a file, previously obtained by calling pack_fopen_chunk().
Returns a pointer to the parent of the sub-chunk you just closed. Returns NULL if there was some error (eg. you tried to close a PACKFILE which wasn't sub-chunked).