On Fri, Aug 11, 2023 at 07:59:12PM +0200, René Scharfe wrote: > > we are defining an inline function with the explicit goal of passing it > > as a function pointer. I don't remember all of the standard's rules > > here. Are we guaranteed that it will create a linkable version if > > necessary? > > I don't see on which basis the compiler could refuse. We can't expect > the function address to be the same across compilation units, but we > don't need that. If there's a compiler that won't do it or a standards > verse that makes this dubious then I'd like to know very much. I seem to recall some quirks where an inline function that is not called directly is not required to be compiled at all, and the compiler can assume that there is a definition available in another translation unit. But I think that only applies when no storage-class specifier is provided. In this case, you said "static", so I think it's OK? It's possible I'm mis-remembering the issues, too. One problem is that pre-C99, you might end up with the opposite problem (a compiled function with visible linkage that conflicts with other translation units at link time). E.g. here: https://stackoverflow.com/questions/51533082/clarification-over-internal-linkage-of-inline-functions-in-c/51533367#51533367 But I think with "static" we should always be OK. > > So I dunno. Clever, for sure, and I think it would work. I'm not sure if > > the extra code merits the return or not. > > Sure, why check types -- script languages get work done as well. (I'm > fresh off a Python basics training, nice quirky language..) But we're > in C land and static typing is supposed to help us get our operations > correct and portable. Don't get me wrong, I like type checking. It's just that doing weird things with the language and pre-processor also carries a cost, especially in an open source project where new folks may show up and say "what the hell is this macro doing?". That's a friction for new developers, even if they're comfortable with idiomatic C. That said... > A good example in parseopt: The patch below adds type checking to the > int options and yields 79 warning about incompatible pointers, because > enum pointers were used in integer option definitions. The storage size > of enums depends on the member values and the compiler; an enum could be > char-sized. When we access such a thing with an int pointer we write up > to seven bytes of garbage ... somewhere. We better fix that. ...I do find this evidence compelling. -Peff
