You wrote:

(* It seems that GPC will get more options than any other existing Pascal

compiler ... :*)

Absolutely true :-)

But I'm not sure if I like this, but I hasten to add that I don't see a better way.

My concern is the following: I've a team of programmers building an extended pascal program. How can I be sure that they don't use some gpc feature? I have the -extended-pascal directive to check if it's Extended Pascal, but how can I check if they use some compiler directive in the source to force the compiler doing something?? This particular directive very probably isn't supported by another Extended Pascal compiler, so I would like to automatically detect and forbid it's use.

Let's add another compiler directive to disable compiler directives? :-)

Or better maybe: using an ISO form of pascal like standard-pascal or extended-pascal, compiler directives are turned off by default and you explicitly have to enable them?

This makes it easier by just compiling the source to see if it is portable.

Groetjes,

Berend.