Re: Problem with ControlFileData structure being ABI depe ndent - Mailing list pgsql-hackers

From Dave Page
Subject Re: Problem with ControlFileData structure being ABI depe ndent
Date
Msg-id 47595939.8000905@postgresql.org
Whole thread Raw
In response to Re: Problem with ControlFileData structure being ABI depe ndent  (Gregory Stark <stark@enterprisedb.com>)
Responses Re: Problem with ControlFileData structure being ABI depe ndent  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-hackers
Gregory Stark wrote:
> "Magnus Hagander" <magnus@hagander.net> writes:
> 
>>>> I guess my advice would be to see if we can define _USE_32BIT_TIME_T
>>>> in port/win32.h and make it go away that way.  It'd definitely be nice
>>>> if MSVC and Mingw builds weren't binary-incompatible.
>>> The attached patch defines it in the MSVC project files along with the
>>> other API-config related macros. It fixes all the offsets so they match
>>> mingw, but the CRC is still different for some as-yet unknown reason...
>> Is the project file really the proper place? Consider an add-on module -
>> wouldn't we want the setting to go in that one as well? meaning we'd have it in
>> a header file instead?
> 
> For an add-on module which is actually using time_t to interface with Postgres
> it had better define _USE_... itself or else it risks having some files use
> them and some not.

Yeah, that was roughly my thinking having run into exactly that problem 
whilst playing around earlier. We also have other 'api config' macros in 
project files (though I appreciate those aren't changing ABI related 
stuff) so it seemed a natural place.

My other thought was that many of the addons this is likely to affect 
will be packaged as additional contrib modules, so they will 
automatically pickup the macro if dropped in /contrib and built from there.

> An alternative is leaving it in the project file but putting something like
> this in c.h:
> 
> #ifdef WIN32
> #ifndef _USE_32BIT_TIME_T
> #error "Postgres uses 32 bit time_t add #define _USE_32BIT_TIME_T on Windows
> #endif
> #endif
> 
> For modules which *do* use time_t this is safer. However for modules which
> don't use time_t it'll be an unnecessary hassle.

Yeah, that might be useful. We could narrow the scope of platforms 
affected by using _MSC_VER instead of WIN32.

/D



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