Provided by: allegro5-doc_5.0.11-2_all 

NAME
al_is_system_installed - Allegro 5 API
SYNOPSIS
#include <allegro5/allegro.h>
bool al_is_system_installed(void)
DESCRIPTION
Returns true if Allegro is initialized, otherwise returns false.
al_is_system_installed(3a... Allegro reference manual()