DOKK / manpages / debian 10 / allegro4-doc / empty_string.3alleg4.en
empty_string(3alleg4) Allegro manual empty_string(3alleg4)

empty_string - Universal string NULL terminator. Allegro game programming library.

#include <allegro.h>

extern char empty_string[];

You can't just rely on "" to be a valid empty string in any encoding format. This global buffer contains a number of consecutive zeros, so it will be a valid empty string no matter whether the program is running in ASCII, Unicode, or UTF-8 mode.

version 4.4.2 Allegro