Re: datetime.h defines like PM conflict with external libraries

Andres Freund <andres(at)anarazel(dot)de> writes:
> On 2017-10-03 16:34:38 -0400, Andrew Dunstan wrote:
>> AFAICT at a quick glance these are only used in a couple of files. Maybe
>> the defs need to be floated off to a different header with more limited
>> inclusion?

> Why not just rename them to PG_PM etc? If we force potential external
> users to do some changes, we can use more unique names just as well -
> the effort to adapt won't be meaningfully higher... IMNSHO there's not
> much excuse for defining macros like PM globally.

I like the new-header-file idea because it will result in minimal code
churn and thus minimal back-patching hazards.

I do *not* like "PG_PM". For our own purposes that adds no uniqueness
at all. If we're to touch these symbols then I'd go for names like
"DATETIME_PM". Or maybe "DT_PM" ... there's a little bit of precedent
for the DT_ prefix already.

regards, tom lane