Interface to running OpenGl GUI Application

Hello

Some Information: A OpenGl GUI is used as a simple visualization tool for testing autonmous function. It reads a log file with object coordinates and displays them. The log file is generated in a simulation loop without using any OpenGL functionality. Every iteration a new log file is gernerated. When the game loop has finished, the OpenGL GUI shows every 100ms one visualisation of the log file beginning with file number 1 until there is no file left.

In order to test my functions i want to interact manually with keys. For Example: pushing the ā€˜Dā€™ key is turning the vehicle.
What i need is a way to call a function, that is hidden behind a Button of the running OpenGl GUI. (The function increments the file number)
Is there a way to control the OpenGl button from my visual studio c++ project?

thx for help

Thx to glutMainLoopEvent() developer