Non recursive makefile example

Question

I've visited many links including Peter Miller's PDF about non recursive make but I still can't find a simple example on how to implement it.

I've googled for hours but many of them seem to be over-complicated and hard to tell the flow of things.

Can somebody show an example of a couple of directories? I'd like to see how the makefile scales as more directories are added.

Maybe for something like:

/src/
|->main.cc

|->dirA/a.cc
|->dirA/module.mk

|->dirB/b.cc
|->dirB/module.mk

/include/
|->main.h
|->a.h
|->b.h

Then have main.o require a.o and b.o to be compiled into one executable.

Thanks for any tips and guidance in advance!

Answer 1

You haven't said much about what you want this system to do. Here's a crude but effective solution:

/src/Makefile:

vpath %.h include

main: main.o
    $(CXX) $^ -o $@

%.o: %.cc
    $(CXX) -c -Iinclude $< -o $@     # not the best way, but maybe the clearest

include dirA/module.mk
include dirB/module.mk

/src/dirA/module.mk:

main: dirA/a.o

dirA/a.o: a.h

/src/dirB/module.mk:

main: dirB/b.o

dirB/b.o: b.h

There is more you can do, once you have this much working.