Please help me with my Makefile ... [Multiple directories]

[robz0rz]

Hello all

I'm having trouble getting my Makefiles to work. I want to organise my code into separate directories as shown below. I'm trying to make it so I can type in make all one time in the root directory and compile my application. The problem is that I can't compile GFX, because there is no entry-point. This is the error I get:

rob@rob-laptop:~/dev/engine$ make all
cd ./gfx ; make GFX
make[1]: Entering directory `/home/rob/dev/engine/gfx'
g++ -c gfx_opengl.cpp
g++ -o GFX gfx_opengl.o `sdl-config --cflags --libs` -lGLU
/usr/lib/gcc/i486-linux-gnu/4.2.3/../../../../lib/crt1.o: In function `_start':
(.text+0x18): undefined reference to `main'
collect2: ld returned 1 exit status
make[1]: *** [GFX] Error 1
make[1]: Leaving directory `/home/rob/dev/engine/gfx'
make: *** [GFX] Error 2

Whereas if I select to compile MAIN first, I get this:

rob@rob-laptop:~/dev/engine$ make all
cd ./main ; make MAIN;
make[1]: Entering directory `/home/rob/dev/engine/main'
g++ -c main.cpp
g++ -o MAIN main.o `sdl-config --cflags --libs` -lGLU
main.o: In function `main':
main.cpp:(.text+0x116): undefined reference to `gfx::init()'
collect2: ld returned 1 exit status
make[1]: *** [MAIN] Error 1
make[1]: Leaving directory `/home/rob/dev/engine/main'
make: *** [MAIN] Error 2

How can I solve this?



File list:

./Makefile
./Makefile.common
./gfx/gfx_opengl.cpp
./gfx/gfx_opengl.h
./gfx/Makefile
./main/main.cpp
./main/Makefile

The Makefiles

## Makefile at .:

CC = g++
CFLAGS = `sdl-config --cflags --libs` -lGLU
PROG = application
TRGTS = GFX MAIN



# Link program
${PROG} : ${TRGTS}
	${CC} -o ${PROG} ${TRGTS}


all : ${PROG}


# Compiling targets
MAIN :
	cd ./main ; make MAIN;

GFX :
	cd ./gfx ; make GFX


# Cleaning
clean :
	rm -f *~ *.o ${PROG}
	cd ./main ; make clean
	cd ./gfx ; make clean

## Common Makefile

CC = g++
CFLAGS = `sdl-config --cflags --libs` -lGLU



# Link program
${PROG} : ${OBJS}
	${CC} -o ${PROG} ${OBJS} ${CFLAGS}


# Compiling sources
%.o : %.cpp
	${CC} -c $<


# Cleaning
clean :
	rm -f *~ *.o ${PROG}



## End of common Makefile

## Makefile at ./gfx:

PROG = GFX
OBJS = gfx_opengl.o


include ../Makefile.common



# Objects
gfx_opengl.o : gfx_opengl.cpp gfx_opengl.h

## Makefile at ./main:

PROG = MAIN
OBJS = main.o


include ../Makefile.common

[drl]

Hi.

From a quick skim, you need to tell make that main depends on gfx.

The last half of O'Reilly's book on make discusses component designs, recursive makes, etc. If this is a start of a large and complex project, you may want to consider obtaining that book or one like it ... cheers, drl

Title: Managing Projects with GNU Make
Author: R Mecklenburg
Edition: 3rd
Date: 2004
Publisher: O'Reilly
ISBN: 0-596-00610-1
Pages: 280
Categories: *nix, development, compiling, building, programming, tools
Comments: Visit O'Reilly Media | Spreading the knowledge of innovators to get the corrections for a large
Comments: number of errors.
Comments: GNU manual: GNU `make'
Comments: 43 page tutorial: http://www.cs.utah.edu/classes/cs563...mentsOfMake.ps
Comments: Conflicting opinions amazon.com; 4 stars, 8 reviews, 2007.05.
Comments: see also cons, scons