On 17/10/2018 23:51, Andres Freund wrote:
>> __builtin_types_compatible_p(const char *, char *) returns false (0) for me.
>
> Right, that's why I added a const, inside the macro, to the type
> specified in the unconstify argument. So typeof() yields a const char *,
> and the return type is specified as char *, and adding a const in the
> argument also yields a const char *.
Yeah, that works. The C++-inspired version also allowed casting from
not-const to const, which we don't really need.
I'd perhaps change the signature
#define unconstify(underlying_type, var)
because the "var" doesn't actually have to be a variable.
Attached is my previous patch adapted to your macro.
I'm tempted to get rid of the stuff in dfmgr.c and just let the "older
platforms" get the warning.
--
Peter Eisentraut http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services