Why aren't include guards or pragma once working?
c++
Solution
If they are linker errors, the most likely cause is probably non-inline functions defined in the header.
If you have a non-inline function in a header that is included in more than one source file, it will be defined in each of those source files ("translation units"), thus the function will be defined more than once, hence the multiple definitions error.
Problem
I'm compiling some code that relies on include guards to prevent multiple definitions of objects and functions, but Visual Studio 2008 is giving me link errors that there are multiple definitions. I don't understand why because I've used code very similar to this before and it hasn't caused problems. I must be doing something dumb but I have no idea what it is. I also tried to take out the include guards and use #pragma once, but I get the same link errors. What should I check for?