You could also concatenate the strings, as they are know at compile time, and use puts or something simpler than printf. puts("FAILED: " #expr ) (Or you could

You could also concatenate the strings, as they are know at compile time, and use puts or something simpler than printf. puts("FAILED: " #expr ) (Or you could keep the printf, as it looks like GCC optimizes it to puts when just used to print a string, without variable interpolation)