The GCC 4.1 manual says: 4.5 Integers ============ [...] Signed `>>' acts on negative numbers by sign extension. but nothing is said about past and future GCC implementations. So, how can I test some implementation-defined features? For instance, something like: #ifdef SOME_MACRO_DEFINED_BY_GCC_IF_RIGHT_SHIFT_IS_WITH_SIGN_EXTENSION /* code that works only where signed `>>' acts on negative numbers by sign extension */ #else /* fallback portable code (slower) */ #endif -- Vincent Lefèvre <vincent@xxxxxxxxxx> - Web: <http://www.vinc17.org/> 100% accessible validated (X)HTML - Blog: <http://www.vinc17.org/blog/> Work: CR INRIA - computer arithmetic / Arenaire project (LIP, ENS-Lyon)
