If I wish to detect if the compiler options include -ffast-math, which macro should I define? This is useful if I want to select which path of the code to compile depending on my needs with just a compiler switch. Eg. for SSE2, __SSE2__(or it's cousin) is defined. Or is there another way to do it. Basically, I want to compile one of the two branches of code with just this compiler switch. Thanks, -- Rohit Garg http://rpg-314.blogspot.com/ Senior Undergraduate Department of Physics Indian Institute of Technology Bombay