#define FOO(bar) create_a_really_long_identifier name(some_function(bar1 + bar2), bar3, bar4);

#define multilinemacro do { (x+5); } while (0); \
printf("a multilinemacro"); \
printf("a multilinemacro2");

int main(int argc, char *argv[])
{
   int a, b;
a = 1; // stupid comment \
b = 2;

return(a+b);
}