What grep command will include the current function name in its output?

Question

I run diff with the -p option so the output will include the name of the function where each change occurred. Is there an analogous option for

Answer 1

As with most text processing operations, it's trivial with awk:

$ awk -v re='return' '/^[[:alpha:]]/{f=FNR"-"$0} $0~re{printf "%s\n%d:%s\n--\n",f,FNR,$0; f="" }' file
1-int func1(int x, int y)
3:  return x + y;
--
5-int func2(int x, int y, int z)
9:  return tmp;
--

The above assumes a function signature is any line that starts with a letter (/^[[:alpha:]]/). If that's not the way your code is written, just tweak to suit.