how to debug multiple files /w using makefile

Hi there,

I am using a simple makefile to build a project that needs debugging, but the methods I need to look at are not in the same file as main(). Can some explain to me how to do this, using gdb and make? Here is the makefike:


all: Swara

Swara: swara.o synth.o unit.o sinewave.o
cc -g swara.o synth.o unit.o sinewave.o -o Swara -lstdc++ -lportaudio -lsndfile

swara.o: swara.cpp swara.hpp
cc -g -c swara.cpp swara.hpp -lstdc++

synth.o: synth.cpp synth.hpp
cc -g -c synth.cpp synth.hpp -lportaudio -lsndfile

unit.o: unit.cpp unit.hpp
cc -g -c unit.cpp unit.hpp

sinewave.o: sinewave.cpp sinewave.hpp
cc -g -c sinewave.cpp sinewave.hpp


thanks if you can help!

rich

GDB will automatically move between files. You don't have to do anything special.

Code:

swara.o: swara.cpp swara.hpp
cc -g -c swara.cpp swara.hpp -lstdc++

synth.o: synth.cpp synth.hpp
cc -g -c synth.cpp synth.hpp -lportaudio -lsndfile

unit.o: unit.cpp unit.hpp
cc -g -c unit.cpp unit.hpp

sinewave.o: sinewave.cpp sinewave.hpp
cc -g -c sinewave.cpp sinewave.hpp

You almost certainly don't want to specify the .hpp files as inputs to gcc, and when using the -c flag, linking isn't done, so you also shouldn't give -lsomething to gcc when using the -c flag (and yes, you are using the -c flag properly).

I would also recommend something like this:

Code:

CFLAGS = -g -Wall -pedantic
CC = cc ${CFLAGS}
...
swara.o: swara.cpp swara.hpp
${CC} ${CFLAGS} -c swara.cpp
...

-Wall will enable warnings - eliminate any warnings you get, as that will most likely make your code more reliable / correct.

A question: Does none of your other .cpp fiels include any of the .hpp files, e.g. I would expect sinewave.hpp to be included in some other file to enable the use of it's content - if so, you should add this header to the dependencies of the other .cpp files that include it. There's few things worse than building a project, and finding out after several debug attempts that the OTHER modules never got rebuilt when you changed a header file, so you're using the wrong (old) data format in the other modules - this is sometimes VERY OBVIOUS, but at other times not so obvious, and you just get very weird bugs where data gets overwritten in random ways...

--
Mats

Ah... thanks for helping me clean it up! It appears that adding header files to the cc command was not allowing the debugger to see the files? As you can see, I'm quite new to makefiles still, just been trying to piece it together through the use of google.

Would this be a good place to ask some questions about the problems I'm having using the Autotools? I'd like to get that working with my project before too long, this was just a temporary solution.

thanks Mats, others,
rich

I suggest using a Makefile like this. You'll have to replace the spaces with tabs.

Code:

OBJECTS = swara.o synth.o unit.o sinewave.o
LDFLAGS = -lstdc++ -lportaudio -lsndfile
TARGET = Swara

# Default target: all
all: $(TARGET)

$(TARGET): $(OBJECTS)
        $(CC) $(CFLAGS) $(OBJECTS) -o $(TARGET) $(LDFLAGS)

# Source files
swara.o: swara.cpp swara.hpp
synth.o: synth.cpp synth.hpp
unit.o: unit.cpp unit.hpp
sinewave.o: sinewave.cpp sinewave.hpp

Make has built-in rules that automatically know how to build .c, .cpp, and other source files.

The blue code can be automatically generated (with the proper dependencies) with

Code:

gcc -MM *.cpp

Also see matsp's suggestions.

And you might perhaps want some targets like this:

Code:

clean:
        rm $(OBJECTS) $(TARGET)
run: $(TARGET)
        $(TARGET)
debug: $(TARGET)
        gdb $(TARGET)

Finally, if you want to set a breakpoint or whatever on line 80 of a different file from the current one in gdb, use

Code:

(gdb) break otherfile.cpp:80

GDB has a pretty extensive help system. You can type help or help breakpoints etc to get more information. And there's always some online manuals and tutorials for gdb. (One on this very site.)

[edit] Oh yes, and if you create a file called, say, all, then the all target won't work properly. You'll have to add

Code:

.PHONY: all clean run

etc if you create files by those names. [/edit]