How do I go to a local variable's definition with Emacs and GNU Global?

Question

Suppose you have a C code like this:

void f1() {
    int var1;

    var1 = 1; // local use of var1
}

void f2() {
    int var1;

    var1 = 2; // local use of var1
}

void f3() {
    int var1;

    var 1 = 3; // local use of var1
}

How do I go to the defition of a local variable with Emacs and GNU Global (gtags.el) while pointing at a local use of it?

I've tried gtags-find-tag (with "var1" as argument) and it doesn't find anything (looks like tags are supposed to be functions) and I've tried gtags-find-symbol, which shows me a list with all three var1 definitions (and possible uses as well).

Answer 1

You do not need the help of Global, but it can be done as a keyboard macro:

• Take a note of the current word, the "var1" in this case
• Search backward using emacs beginning-of-defun lisp function
• Search forward for "var1", this is usually the definition of var1 as it is the first appearance of var1 in the current defun.

Starting from this kerboard macro, I wrote the following lisp function:

(defun bhj-isearch-from-bod (&optional col-indent)
  (interactive "p")
  (let ((word (current-word)))
    (beginning-of-defun)
    (setq regexp-search-ring (cons (concat "\\b" word "\\b") regexp-search-ring))
    (search-forward-regexp (concat "\\b" word "\\b"))))