Thanks. However that's exactly what it appears to do, i.e. when I compile with the option -mpopcnt, the macro __POPCNT__ is defined, but is not defined when the option is not given. That's exactly what I was looking for! Thanks again. -- View this message in context: http://gcc.1065356.n5.nabble.com/Check-for-command-line-option-in-my-header-file-tp1282119p1282140.html Sent from the gcc - Help mailing list archive at Nabble.com.
