c++ - what is Main Loop Abstraction concept? -

I am using AC / C + + API which uses the concept of main loop intangible, so I get confused How do the flow of the program work in the loop intangible concept? Is there any document for this ?? If anyone knows, then explain it with an example. So, suppose you have a lavish library (for example, OpenGL).

It starts some things with callback and then it enters a while (1) loop in which it checks events from the users of the library.

Consider a GUI program every time you press a key or move your mouse or click on a button, then an event will loop up (via a line method or Through voting, now it really does not matter). It calls the handler function associated with the loop callback, to make sure that the call is done properly with proper parameters and checks.

Have not used it, every time the programmer wanted to use a GUI application in which she had to write her own loop with scratch.