On Tue, 10 Oct 2017, Martin Sebor wrote: > > I know of pre-existing code-bases where a type-cast to type: > > void (*) (void); > > > > .. is already used as a generic function pointer: libffi and > > libgo, I would not want to break these. > > Why not fix them instead? They're a part of GCC so it should > be straightforward. It doesn't seem like a good tradeoff to
Sometimes an interface needs to store an arbitrary function type for which an ABI-compliant call ends up being constructed at runtime from assembly language (or from non-C, in general). That's the sort of thing libffi does - so it inherently needs to be able to take pointers to arbitrary function types, which thus need to be converted to a generic function type, and the de facto generic function pointer type in C is void (*) (void). (C11 6.11.6 says "The use of function declarators with empty parentheses (not prototype-format parameter type declarators) is an obsolescent feature.", so void (*) () is best avoided.) Likewise interfaces such as dlsym (which happens to return void * along with a special case in POSIX requiring conversions between void * and function pointers to work, but void (*) (void) is the natural type for such interfaces to use). -- Joseph S. Myers jos...@codesourcery.com
