where to put path to include file
 

I'm writing a c++ app and have a certain .h file that I want the machine to always go look for in a specific dir. I thought the place to add this path was in PATH but that doesnt work. Besides which, all the PATH entries are going to various /bin dirs, whereas this .h file is not in a /bin dir. Any idea where one is supposed to add this path (once and for all)...
I'm in SuSe linux
thanks

BTW I do know that I can put the path into my makefile, but thats a one-by-one basis. I was hoping for a more permanent fix.

/usr/include is a good place.