Where can I get the source and header files for the gnu.org Simple Makefile?

Question

Where can I get the source and header files for the gnu.org "Simple Makefile" example?

I reallywant to experiment with this very good example, except the fact that I can't find the referenced source & header files.

Any pointers?

Answer 1

Does the exact content of the files REALLY matter here? I believe the purpose of the linked manual is to describe the workings of the make, to show the syntax and semantics of writing and using a makefile, not for building any particular real application. The names used are just a notion. You can simply create the files with that particular name, if you want, and put some dummy functions.

For your reference, you can check this alternative link which has the source codes for the used files, too. This is very simple example but should be enough to give you the idea.

Answer 2

To create minimal files with which the sample Makefile will work, you can run:

touch {kbd,command,display,insert,search,files,utils}.c \
      {defs,command,buffer}.h;\
      echo 'int main(){}' > main.c

---

Explanation:

The minimum C file that will compile into an object file is the empty file. For linking to succeed, you need one and exactly one main function. The above code just creates empty .c and .h files mentioned in the sample Makefile and the main.c file with the main function.

As has been said, the contents don't matter so you might as well make it the minimum that works.

The C build system and the interaction of .c and .h files

In a real-case scenario, the role of .h files is just that they get #included from .c files. #inclusion is a literal copy and paste—you might as well replace each #include directive with the exact contents of what's getting included because that's exactly what the compiler will do.

The files that depend on .h files (according to the directives in the Makefile) should normally correspondingly #include the same header files.

Header-file dependency deduplication

Real-world Makefiles normally don't duplicate this info, but instead create header dependency files out out .c files (based on the #include directives contained within them) with something like (the header dependency files usually have the .d suffix):

#A makefile rule with some dynamic variables (more advanced make)
%.d: %.c
    $(C) $(CFLAGS) -MM -MF $@ -MT $*.o $<

#include will remake the dependency files if they need to be
-include $(CLIENT_SRC_C_D)

(tup, which is a great Make alternative does this automatically and language-agnostically based on filesystem reads).