Using a makefile to compile a program using SDL

Hello

I am trying to learn SDL from this tutorial ( http://lazyfooproductions.com/SDL_tu...on02/index.php ) but I am having some troubles compiling with make.

If i just use: "g++ -lSDL main.cpp -o play" the program works fine.

But if I instead use this makefile the program quits with a Segmentation fault

Code:

---

CXX = g++

LDFLAGS = lSDL

OUTPUT = play

sources = main.cpp

OBJS = ${sources:.cpp=.o}

${OUTPUT}:${OBJS}
        ${CXX} -${LDFLAGS} ${OBJS} -o ${OUTPUT}

---

If I edit my makefile to this:

Code:

---

CXX = g++

LDFLAGS = lSDL

OUTPUT = play

sources = main.cpp

OBJS = ${sources:.cpp=.o}

${OUTPUT}:${OBJS}
        ${CXX} -${LDFLAGS} ${sources} -o ${OUTPUT} #using sources instead of OBJS

---

the program runs with no problems. So I think it has something to do with the *.o file but I have no idea what.

Does anyone know why the program gives a seg-fault when it is compiled using *.o files?

Do you have a log of the commands executed during the make process?

And is it make which crashes, or the IDE, or the program you managed to create?

It is the program that crashes. It compiles with no problems. It makes no difference if I run make from within my IDE (emacs) ot just in a terminal. What I think is wired is that it only happends when I use .o files.

Does

g++ -c main.cpp
g++ -lSDL main.o -o play

also crash?

OK now I am confused.
Your command works fine and after I ran it my makefile suddenly started working. The manual says that the -c flag compiles the file without linking it.
How come running it suddenly made my makefile work?

> How come running it suddenly made my makefile work?
The only thing I can think of is there is something messed up with file time stamps, and you were compiling with an older .o file than you expected.

I also noticed with the OBJS form, that since you don't directly specify the name of the source file, it goes looking through the implicit rules looking for something to create a .o file with.

On my system, I saw
cc -c -o play.o play.c
rather than
g++ -c -o play.o play.cpp

So if you have a main.c and a main.cpp, the implicit rule favours the C source over the C++ source.

This is what I mean by a makefile log

Code:

---

$ make -f Makefile
g++    -c -o play.o play.cpp
g++ -lm play.o -o play

---

I am a Little confused. In the line "sources = main.cpp" I would say that I specify the source file.

Your makefile is correct.

Check your directory, do you have play.c AND play.cpp

Post your makefile log.

I have never had main.c. Emacs creates a file named main.cpp~ but it has never given any problems before. And even if it is there make works fine now.

Code:

---

make -f Makefile
g++    -c -o main.o main.cpp
g++ -lSDL main.o  -o play

---

I don't understand why but it seems to be working just fine now.

Salem >> Thank you very much for your time