On Sat, Dec 30, 2017 at 10:31:45AM -0500, Tom Lane wrote: > Surely bool and bool8 should have identical Datum representations, > so I'm not sure they need different DatumGet/GetDatum macros.
[... refresh update ...] Yeah sure. I am a bit disturbed by the fact that DatumGetBool() enforces a case to bool though. > Although this opens up another point: just above those macros, > postgres.h says > > * When a type narrower than Datum is stored in a Datum, we place it in the > * low-order bits and are careful that the DatumGetXXX macro for it discards > * the unused high-order bits (as opposed to, say, assuming they are zero). > * This is needed to support old-style user-defined functions, since depending > * on architecture and compiler, the return value of a function returning char > * or short may contain garbage when called as if it returned Datum. > > Since we flushed support for V0 functions, the stated rationale doesn't > apply anymore. I wonder whether there is anything to be gained by > changing DatumGetXXX and XXXGetDatum to be simple casts (as, if memory > serves, they once were until we noticed the stated hazard). Or, if > there's still a reason to keep the masking steps in place, we'd better > update this comment. 23a41573 did not do it rightly visibly, and 23b09e1 got it better, still GET_1_BYTE() was getting used only because of V0 functions being used in contrib/seg and because of the way MSVC 2015 handles boolean evaluation as per thread [1]. In short, your argument for a switch to simple casts makes sense for me. [1]: https://www.postgresql.org/message-id/e1atdps-0005zu...@gemulon.postgresql.org -- Michael
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