Can a C macro contain temporary variables?

Question

I have a function that I need to macro\'ize. The function contains temp variables and I can\'t remember if there are any rules about use of temporary variables in macro subs

Answer 1

There are only two conditions under which it works in any "reasonable" way.

1. The macro doesn't have a return statement. You can use the do while trick.

   #define macro(x) do { int y = x; func(&y); } while (0)
   

2. You only target GCC.

   #define min(x,y) ({ int _x = (x), _y = (y); _x < _y ? _x : _y; })
   

It would help if you explain why you have to use a macro (does your office have "macro mondays" or something?). Otherwise we can't really help.