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	Mon, 21 May 2018 00:36:53 -0400
From: Tom Lane <tgl@sss.pgh.pa.us>
To: Thomas Munro <thomas.munro@enterprisedb.com>
cc: PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Subject: Re: Allowing printf("%m") only where it actually works
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Comments: In-reply-to Tom Lane <tgl@sss.pgh.pa.us>
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... and, while we're thinking about this, how can we prevent the reverse
problem of using strerror(errno) where you should have used %m?  That
is evidently not academic either, cf 81256cd.

I am wondering whether the elog/ereport macros can locally define some
version of "errno" that would cause a compile failure if it's referenced
within the macro args.  But I'm too tired to work it out in detail.

			regards, tom lane