List unused C/C++ functions

You have a C/C++ project. It is more than a few files, including some libraries. Now you want to know whether you can get rid of / comment out some of the functions that are never used.

There is no well-known FREE and OPEN SOURCE tools that can do this for you as of 2011, but a not-very-well-known tool called "callcatcher" created by Caolan does the job beautifully.

First, to download the callcatcher, go to the official website: http://www.skynet.ie/~caolan/Packages/callcatcher.html

It is written in Python. So you may want to install it by becoming a root or use sudo.

To use the tool, you need to change ALL your make files to prepend "callcatcher" to your "gcc/g++" command. For example, in your original Makefile, you have

CC=gcc
AR=ar

Now change it to

CC=callcatcher gcc
AR=callarchive ar

When you are done compiling, to see which functions is not used, do:


callanalyse MY-EXE-FILE

Another caveat is that you cannot compile multiple times at the same time, like this


$(CC) -o main main.c lib1.c lib2.c  (This is bad for callcatcher)

Instead you need to change it to something like this, so that you only compile one file at a time, then link it:

%.o:%.c

   $(CC) $(CFLAGS) -c $^

main: $(OBJS)

    $(CC) -o $@ $(OBJS)