Find function definition in C++

Question

I have a C++ project on remote machine which compiles with makefile. No ide available, only vim and commandline. I found a function in the sourcecode and want to find its definition. How can I do that without manually looking all -I directories and source files? Is it possible to stop makefile after preprocessing phase and lookup in the resulting sourcefiles?

Answer 1

You can use ctag and cscop to browse the code on vi. If you are not comfortable with that then use a

grep -rn funtion_name ./

in the home dir of the source code, and manually look for the definition in the result set.

Answer 2

The easiest solution would be to use grep (with find to get results very fast) like this:

find srcDir -name "*.c" -o -name "*.cpp" -print0 | xargs -0 grep "functionName"

The Makefile based solution is to change the linking so you ask for a verbose location of a function definition like this (if you use GCC) (you can also do that on the command line with "make LDFLAGS=...seebelow...")

# In your makefile, locate this:
LDFLAGS:= ...
# Replace by this
LDFLAGS:= -Wl,--trace-symbol=functionName

This results in:

$ gcc -o test main.o -Wl,--trace-symbol=main
/usr/lib/gcc/x86_64-linux-gnu/4.4.5/../../../../lib/crt1.o: reference to main
main.o: definition of main

This solution is useful if you have plenty of similar function name, and you actually want the one that's used in the final binary.