C/C++ header and implementation files: How do they work?

Question

This is probably a stupid question, but I\'ve searched for quite a while now here and on the web and couldn\'t come up with a clear answer (did my due diligence goo

Answer 1

The preprocessor includes the content of the header files in to the cpp files (cpp files are called translation unit). When you compile the code, each translational unit separately is checked for semantic and syntactic errors. The presence of function definitions across translation units is not considered. .obj files are generated after compilation.

In the next step when the obj files are linked. the definition of functions (member functions for classes) that are used gets searched and linking happens. If the function is not found a linker error is thrown.

In your example, If the function was not defined in myfunction.cpp, compilation would still go on with no problem. An error would be reported in the linking step.