and you can figure if a specific OpenGL function is available using :
Not to confuse with :
isExtensionAvailable(String glExtensionName) !
Ok, thanks. So with isExtensionAvailable("GL_ARB_multitexture") you can see if that multitexture extension is available. The glActiveTextureARB() function being one of this extension's functions. A isFunctionAvailable("glActiveTextureARB") will result in true in this case.
But I can't imagine at the moment why I should want to ask for the function. I learned from your above posts that I ask for the extension GL_ARB_multitexture (with isExtenionAvailable) and then I should be able to call glActiveTextureARB(...).
So why a isFunctionAvailable...?