I'm having trouble using my homemade .h files in my multi-source projects. If I I only include the .h in one of the sources I can't use it in the others. But if I include it other sources it's considered redefining the include and it won't compile. Other .h's besides the ones that I make do this to. I've noticed that some though (such as iostream) don't have this problem and I could include it in the same source 10 times if I wanted to. can someone please help me out with this so that I can make header files that can be declared more than once in the same project?