Re: reference to undefined macro _MSC_VER - Mailing list pgsql-bugs

From bryanh@giraffe-data.com (Bryan Henderson)
Subject Re: reference to undefined macro _MSC_VER
Date
Msg-id 10438.bryanh@giraffe-data.com
Whole thread Raw
In response to Re: reference to undefined macro _MSC_VER  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-bugs
>As for -Wundef, it seems rather impractical to turn that on anyway given
>that it produces numerous other warnings --- a quick check in HEAD shows

It looks like my point was missed.  I'm talking about compiling user code that
interfaces with Postgres.  I'm specifically talking about server extensions,
so it _is_ sort of part of Postgres and some restrictions make sense.  But
it's compiled outside of the Postgres build, and that makes a big difference.
Often, the point of a C-language extension is to bridge between Postgres and
some other world, so Postgres can't completely command the compilation (or
runtime) environment -- the extension has to meet the requirements of the
other world as well.

After I added an #ifdef, none of my server extensions encountered an
undefined macro warning, so it does help.

Incidentally, for those who have never used -Wundef: It's extremely
productive.  We've all lost way too much time on bugs that happen because in
the tangle header files, ifdefs, and source code updates, we forget to define
a macro.  That's why all of my code is designed to use #if instead of #ifdef
and compile with -Wundef -Werror.  I find it so valuable that I even maintain
workarounds and local patches of other people's interface header files
(e.g. Postgres c.h) to allow me to use it.  Of course, it would be better
still if Postgres came to me already compatible with this style of
development.

>I can't get terribly excited about that.

The thing is, you don't have to get terribly excited.  Just slightly
interested.  Because it just takes two lines of code with zero chance of
messing up anything to provide something with a practical use that makes
logical sense as well.

--
Bryan Henderson                                   San Jose, California

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