How to detect header changes in make dependency list

Question

After almost a decade of C# and VC++ coding, I am getting back to a linux – g++ - make – emacs environment.

Trying to refresh my memory about writing a make file I did not have many problems, but I stumbled in the following issue, that I admit I do not remember how I solved it in the past:

Let’s say that a particular .cpp file have some dependencies to several other header files (setting aside its corresponding header which is easy to handle)… What is the best way to detect that some of the .h were changed?

I certainly do not like the idea of placing them in my target – depend list since this is a manual and error prone process!

The easy answer is of course to build clean whenever there is a .h change but I cannot really recall what was the standard way….

In VC++ I did not have to deal with this since the IDE was very good at handling dependencies…

Answer 1

Look at automated dependencies. gcc with the -M -MD -MT etc. flags will parse your file and compute dependencies. Pass them through sed. There are many examples that google will find.