Any program or trick to find the definition of a variable?

Question

Many times when I am watching others code I just want to find where and how a variable is defined. Normally what I do now is look for the type of the variable until I find the definition, that is very time consuming. And I guess that there are some tools that can help me in this rutinary situation. Any suggestion in some tools or commands to help me in this task?.

I know that using a GUI and creating a project this is done automatically I am talking of a way to do this without a GUI. I am working with only text mode. I am running under Linux and I am using C/C++, but suggestions for other languages are welcome.

Thanks a lot.

A possible solution

Michel in one of his comments propose a simple an effective solution define again the variable, in that case in compilation time, the compiler will inform where is the previous definiton. Of course to apply this solution we need to think previously in the locality of the variable.

Answer 1

You've already given the most appropriate tool: an IDE. This is exactly the kind of thing which an IDE excels at. Why would you not want to use an IDE if you're finding development painful without one?

Note that Emacs, Vim etc can work as IDEs - I'm not talking about forcing you the world of GUIs if you want to stay in a text-only situation, e.g. because you're SSHing in.

(I'm really not trying to be rude here. I just think you've discounted the obvious solution without explaining why.)

Answer 2

Edit: OK, you say you're using C++. I'm editing my response. I would use the C preprocessor and then grep for the variable. It will appear in the first place.

cpp -I...(preprocessor options here) file.cpp | grep variable

The C preprocessor will join all the includes that the program uses, and the definition has to be before any usage of that variable in the file. Not a perfect thing, but without an IDE or a complete language description/managing tool, you only have the text.

Another option would be using ctags. It understands the C and C++ syntaxes (among others), and can be searched for variables and functions using command line tools, emacs and vi, among others.