identity_matrix, identity_matrix_f - Global containing the identity matrix. Allegro game programming

       Global variables containing the 'do nothing' identity matrix. Multiplying by the identity matrix  has  no
       effect.

Allegro                                           version 4.4.3                         identity_matrix(3alleg4)

       identity_matrix,  identity_matrix_f  -  Global  containing  the identity matrix. Allegro game programming
       library.

#include<allegro.h>externMATRIXidentity_matrix;externMATRIX_fidentity_matrix_f;