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ALLEGRO_PI(3)                                                    ALLEGRO_PI(3)

NAME
       ALLEGRO_PI - Allegro 5 API

SYNOPSIS

              #include <allegro5/allegro.h>

              #define ALLEGRO_PI        3.14159265358979323846

DESCRIPTION
       C99 compilers have no predefined value like M_PI for the constant <pi>,
       but you can use this one instead.

Allegro reference manual                                         ALLEGRO_PI(3)