stdlib.h in cocoa.h?

I'm slowly working my way through this book Introduction to OpenGL (perhaps too slowly... I think my understanding of C / Objective-C / Objective-C 2.0 / Cocoa / Cocoa Touch are all slipping away as I read this... hopefully looking over my previous projects will bring back the memories of how it all works...) and I noticed that one of the examples in it has:

Code:

#include <GL/gl.h>
#include <GL/glu.h>
#include <GL/glut.h>
#include <stdlib.h>

I changed it to:

Code:

#import <Cocoa/Cocoa.h>
#import <OpenGL/gl.h>
#import <OpenGL/glu.h>
#import <GLUT/glut.h>

I ran it and it works fine... but it made me wonder about stdlib.h. Is it already included in cocoa.h? Or is it just that the example in the book didn't need stdlib.h to work properly and that in the future I may need to include it? (Where would I find the framework that includes it anyways?)

 

I looked in the header files of Cocoa only... it didn't occur to me that it would be buried so many layers deep. But it confirms what I already suspected.

Oh?

Odd that the examples in the book include all 3 then. Well, I changed it to only import glut.h now (and it still works.)