I've to do a shool project where i have to write a messager in C with a friend of mine. We have to split our programm in to pieces <- Teacher said that. I do the GUI and he sends and revieves the XML-Formated messages.

Now here is the Problem:

I want to open his programm with system("his pro.exe"); so his programm starts, then it waits. But while it is waiting, my programm should go on, but it doesn't. My programm is waiting for a return 0;
Eventually his programm should stay opened in the background waiting for his file, which its recieves and my pro should work on.

Maybe there is something to return a value without closing the programm.

So I don't know what to do now. Please help me.

PS: sorry for my english I'm german.

You probably would be best to look into a threading library and make your program multi-threaded.