On Wednesday, 6 January 2021 at 21:27:59 UTC, H. S. Teoh wrote:
It must be unique because different functions may return different sets of error codes. If these sets overlap, then once the error propagates up the call stack it becomes ambiguous which error it is.
I don't think this is the case. If you analyse the full program then you know the functions that interact. All you need to do is dataflow analysis.
I also don't think there should be a specific error-code, I think that should be left implementation defined. The program should just specify a set of errors. Then it is up to the compiler if that for a given call can be represented using some free bits in another return value as a nullpointer or whatever.
If speed is what is sought, well, then design for it. :-)
