Creating my own makefile [Error 255]

Question

I have been enjoying the luxury of coding with an IDE that writes my makefile's for me, Iv decided that I have been 'short cutting' for far to long, so I have read a few manuals and watched a few videos on makefiles and have a makefile semi-done, the only trouble that I'm having is I'm not sure how to link libraries.

CPPS := $(shell ls src/*cpp)
TEMP := $(subst src/,obj/,$(CPPS))
OBJS := $(subst .cpp,.o,$(TEMP))
HEADERS := $(shell ls inc/*.h)
EXEC := bin/testfile

all: $(EXEC)

$(EXEC) : $(OBJS) $(HEADERS)
g++ -I inc/ $(OBJS) -o $(EXEC) -lSDL -lGLU
$(EXEC)

obj/%.o: src/%.cpp
g++ -Wall -I inc/ -c $< -o $@

ps: just incase I am saying the wrong thing when I say 'Library flags' I mean -lSDL -lGLU etc...

Wherever I put them they dont seem to work.

This is the error I get when I insert the lib flags, make: *** [bin/testfile] Error 255

The Error 255 is produced by make as a result of its command shell not being able to find a command for a particular rule.

If i dont include them I get standard 'undefined' messages.

Any help with this would be greatly appreciated! Thank you

Solution

It looks like you are trying to run your executable after you have built it?

It that case the problem is that you don't have your current directory on the PATH; so make can't find $(EXEC).

You should probably just do ./$(EXEC) to run it directly.

And you should move executing the program to a different (PHONY) target, so that you can do just the build step on its own, and run when $(EXEC) doesn't need to be built.

(I'm assuming the lack of tabs is just stackoverflow formatting, as otherwise make would be complaining).

Comments

[Elgoog]

Your bang on the money there! thanks, am I linking the libraries correctly? my prog doesn't seem to be executing, but no error displays. Yet when built using an IDE it works just fine...

[Douglas Leeder]

@Elgoog I'm afraid you haven't provided enough information; Have you made the changes I suggested? I'd removing executing the program from your Makefile, and running it directly - then it's easier to see what's going on.