Hi Alex, >Is it possible? It is POSSIBLE, but you'd have to write your own pre-pre-processor. (Perhaps in Perl?) Without doing to that extra-ordinary effort, it isn't possible with the pre-processor. AFAIK. Or you could change the line to read... #error BUG : 100 != 200 ...but I presume that defeats the intent of having the token macro-expanded. You could also modify your GCC to perform macro expansion on the error line. That may be more effort than writing your own pre-pre-processor (unless you are already familiar with GCC internals). And you'd have a custom one-off pre-processor in your GCC. Pre-processor info here <http://www.delorie.com/gnu/docs/gcc/cpp_62.html>. HTH, --Eljay
