include folder for C++

[Red Squirrel]

If I make a custom header that I want to use in multiple programs, which folder do I have to put it in? I tried /usr/include as it seems to have lot of .h files, but it does not seem to work. Any other folder I should try?

 

[Red Squirrel]

nm I had \ instead of / in my include. (ported app from windows to Linux)