Problem with converting my code from C to C++

I’m pretty new to this. I’ve been using MinGW and Msys, I have been successfully creating programs in C but when I try to convert it over to C++ I get all sorts of problems. One, it wont recognize my glutTimerFunc as valid and tells me my glOrtho has too many arguments even though it doesn’t. Any help would be appreciated.

Ensure that the function is actually a function (not a method) and has C linkage.

Post the actual code, along with the actual error message.

Thanks! It was an animation method not a function. But now that brings up another question (if you know the answer), why is it when I compiled the program in C it didn’t care whether it was a function or not but in C++ it does even if I don’t use the value that was passed into it?