> Use POSIX Ada 1003.5. It has everything you want, and should work across > almost all OS systems, especially UNIX. All vendors of Ada compilers support > POSIX Ada to my best knowledge. > > Doing anything else is non-portable because OS interfaces are non-portable. Even this may not be 100% portable. For example, I had code in Apex that I had to modify for GNAT, because GNAT (Florist) provided the routine overloaded for String and Wide_String (Apex had only String) and the two vendors had different parameter names. I did not send either vendor a bug report because I cannot afford to buy the official POSIX standard (so I can't tell whether one or both is compliant).