al_get_opengl_proc_address man page

al_get_opengl_proc_address — Allegro 5 API

Synopsis

#include <allegro5/allegro_opengl.h>

void *al_get_opengl_proc_address(const char *name)

Description

Helper to get the address of an OpenGL symbol

Example:

How to get the function glMultiTexCoord3fARB that comes with ARB's Multitexture extension:

// define the type of the function
ALLEGRO_DEFINE_PROC_TYPE(void, MULTI_TEX_FUNC,
                         (GLenum, GLfloat, GLfloat, GLfloat));
// declare the function pointer
MULTI_TEX_FUNC glMultiTexCoord3fARB;
// get the address of the function
glMultiTexCoord3fARB = (MULTI_TEX_FUNC) al_get_opengl_proc_address(
                                                        "glMultiTexCoord3fARB");

If glMultiTexCoord3fARB is not NULL then it can be used as if it has been defined in the OpenGL core library.

Note: Under Windows, OpenGL functions may need a special calling convention, so it's best to always use the ALLEGRO_DEFINE_PROC_TYPE macro when declaring function pointer types for OpenGL functions.

Parameters:

name - The name of the symbol you want to link to.

Return Value

A pointer to the symbol if available or NULL otherwise.

Referenced By

al_get_opengl_extension_list(3).

Allegro reference manual