glutIconifyWindow man page
glutIconifyWindow — Iconify the current window
OpenGLUT - window
Most window systems have some kind of ``minimized'' or ``iconified'' state for windows. All systems currently supported by OpenGLUT do so. The exact meaning of iconification is somewhat system-dependant, but this makes a request of the window system to place the window into this state.
Graphic output is usually suspended in this form. User input may be partially or wholly suspended.
If and when your window is iconified by the window system, it may be uniconified at any time by the system. This usually happens at the request of a user. Because of this, you should not use this function to hide a window. Rather, it is to help unclutter the user's display, and is more or less consensual with the user. Use glutHideWindow() if you want to hide the window entirely.
Applies only to onscreen, top-level windows.
Not guaranteed to have any effect; effect may be arbitrarily delayed.
There is no callback that specifically tells you when (or if) your window is iconified.
glutSetIconTitle(3) glutHideWindow(3) glutShowWindow(3)