Linux Makefiles

[Captain Cosine]

I've been searching for days and reading about using makefiles on linux and I cannot, for the life of me, get it to work correctly.

Let's say I have three files: Finances.cpp Parse.cpp and Parse.h

Finances.cpp has several calls to a function named parse whose definition is in Parse.cpp. Finances.cpp includes Parse.h which contains the prototype of the function named parse.

CXXFLAGS =	-O2 -g -Wall

OBJS =		Finances.o

LIBS =

TARGET =	Finances

Finances:	Finances.o
	$(CXX) $(CXXFLAGS) -o Finances Finances.o
	
Finances.o:	Parse.h Parse.cpp
	$(CXX) -c Finances.cpp

all:	Finances

clean:
	rm -f $(OBJS) $(TARGET)

I know this is not correct, but this is one of the millions of variations I have tried. What's odd is that if I were to replace the prototype in Parse.h with the definition from Parse.cpp, it works perfectly fine.

I keep getting undefined reference to 'main' or 'parse' errors.

Could someone please point me in the right direction?

If it helps, my OS is Ubuntu 12.04 LTS (Precise Pangolin) 32-bit, my IDE is Eclipse, and my compiler is g++ 4.6.3 (I think?)

[ne555]

CXXFLAGS = -O2 -g -Wall

#Compile every unit.
OBJS = Finances.o Parse.o

LIBS =

TARGET = Finances

#The definitions are in the object files. The application depends on them
Finances: $(OBJS)
	$(CXX) $(CXXFLAGS) -o Finances $(OBJS)

#Don't depend on others cpp. That's the idea.
#Put you need to recompile if an included header changes.	
Finances.o: Finances.cpp Parse.h 
	$(CXX) -c Finances.cpp

#Ditto for the other objects
Parse.o: Parse.cpp Parse.h 
	$(CXX) -c Parse.cpp

all: Finances

clean:
	rm -f $(OBJS) $(TARGET)

The makefile will mimic what you do in the command line
By instance you could link all the sources with

$ g++ *.cpp -o program.bin
#or
$ g++ -c *.cpp
$ g++ *.o -o program.bin

Of course, the idea is to avoid recompiling when you don't need.

[Captain Cosine]

Thanks a lot. At first, your suggestion still threw an undefined reference to 'parse' error, but then I removed the inline from the function prototype and definition then built again with success. I suspect I tried your suggestion before and the inline was the problem all along. But thanks again for the help.

Any ideas why the inline was causing the issues?

[ne555]

Because inline and template functions must be defined in headers.

[Captain Cosine]

Ahhh. Never knew that. Thanks again :)