file_size_ex - Returns the size of a file in bytes. Allegro game
programming library.
#include <allegro.h>
uint64_t file_size_ex(const char *filename);
Returns the size of a file, in bytes. If the file does not exist or an
error occurs, it will return zero and store the system error code in
errno.
file_exists(3alleg), file_time(3alleg), expackf(3alleg)