Quote:Original post by Gink
So they are used for convenience and not because they are needed?
In the same way that C++ is used for convenience, and not because we can't do everything in assembly.
The thing is that they can accept ANY (appropriate) function, so unrelated bits of the program can interoperate better. For example, in the GLUT library they use callbacks a lot, which looks something like this:
//==VVV== Inside the GLUT Library ==VVV==typedef void (* f_void_void )( void );f_void_void display_function;void glutDisplayFunc( f_void_void function ) { display_function = function;}void glutMainLoop ( void ) { while ( 1 ) { //... display_function(); swap_buffers(); }}//==^^^== Inside the GLUT Library ==^^^==//==VVV== Inside your program ==VVV==#include <GL/glut.h>void render( void ) { //...}int main ( void ) { //... glutDisplayFunc( render ); glutMainLoop();}In order to have glutMainLoop allways call render() without function pointers, you'd have to edit the GLUT source code (which would be a pain in the butt) and require that each program have their own version of the GLUT library instead of sharing a single one.
Hope this helps to explain :-).
