#if __GXX_RTTI Serial.println("GXX test: RTTI enabled"); #else Serial.println("GXX test: RTTI not enabled"); #endif tells me if RTTI is enabled or not. However: #if __cpp_rtti Serial.println("cpp test: RTTI enabled"); #else Serial.println("cpp test: RTTI not enabled"); #endif always tells me that RTTI is not enabled. I don't know if that's what you expected I would find or not, but I don't suppose it matters - I got what I need. Thank you both very much! -- Sent from: http://gcc.1065356.n8.nabble.com/gcc-Help-f629689.html