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

       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.

Allegro                                           version 4.4.3                            empty_string(3alleg4)

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

#include<allegro.h>externcharempty_string[];