Jan, some of the points made e.g. You should perhaps assume at least some intelligence are perfectly valid.
I do "assume some intelligence", but what about "assume some knowledge", how much is an IQ of 250 worth if you have never seen a quasi-bidirectional port described.

.I see the +++ marks and assume they originate from members that are of the opinion "it should not be necessary to include all that sh.. to get an answer".

While, in many/most instances the brand of compiler may be irrelevant, I am of the opinion it is better to insist on it always being mentioned than having to push and pull to get it revealed in the cases where it is relevant. the same goes for the exact derivative "a 80C51" can, today mean virtually anything.

So, in short derivative and toolset should always be in the original post, then it is there if needed, and, if not, the OP has 'wasted' less than 10 seconds.

Erik