On Tue, Oct 16, 2018 at 2:30 AM Andres Freund <and...@anarazel.de> wrote: > This just reminded me that a couple times I wanted a cast that casts > away const, but otherwise makes sure the type stays the same. I don't > think there's a way to do that in C, but we can write one that verifies > the cast doesn't do something bad if gcc is used: > > #if defined(HAVE__BUILTIN_TYPES_COMPATIBLE_P) > #define unconstify(cst, var) > StaticAssertExpr(__builtin_types_compatible_p(__typeof(var), const cst), > "wrong cast"), (cst) (var) > #else > #define unconstify(cst, var) ((cst) (var)) > #endif > > Does anybody besides me see value in adding a cleaned up version of > that?
Under what circumstances would we consider this to be a legitimate thing to use? I think if we add something this, we'd better accompany it with some detailed and very clearly-written statements about when you're allowed to use it. Otherwise, I predict that people will use it in cases where it's not actually safe, and we'll end up with low-grade bugs. -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company
