Thread: Preprocessor trick for variable number of args

I know I've seen something like this before, but it's been a while and I can't get it to work. Does this ring a bell for anyone...

Code:

#include <stdio.h>

#define DEBUG(t)  fprintf(debug_out, t)

int main(void)
 {
  FILE* debug_out = fopen("debug.txt", "w");

  DEBUG("This is only a test...\n");
  DEBUG(("1 = %i\n", 1));
  DEBUG("This was only a test...\n");

  fclose(debug_out);

  return 0;
 }

The theory is that if you encase printf's arguments in parentheses, the macro will take them as a single argument, and everything works fine...except I'm forgetting something, and the compiler simplifies

Code:

("1 = %i\n", 1)

to just

Code:

1

Any thoughts? Thanks in advance.