Hi Dale, > how do I determine what the appropriate preprocessor variable that would indicate for example, being on a Linux platform vs an AIX platform. Refer to the GCC documentation for that platform, man gcc Use this trick to view the predefined preprocessor identifiers echo '' | gcc -E -dM -x c - | sort Hopefully the relevant one is obvious. (Sometimes there are a few that look appropriate, which requires a little more documentation diving investigation.) HTH, --Eljay
