Re: Allowing printf("%m") only where it actually works

Tom Lane <tgl@sss.pgh.pa.us>

From: Tom Lane <tgl@sss.pgh.pa.us>
To: Andres Freund <andres@anarazel.de>
Cc: Michael Paquier <michael@paquier.xyz>, Thomas Munro <thomas.munro@enterprisedb.com>, Alvaro Herrera <alvherre@2ndquadrant.com>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2018-10-09T00:47:16Z
Lists: pgsql-hackers

Attachments

So, circling back to the very beginning of this thread where I worried
about all the compile warnings we get on NetBSD-current, I'm pleased
to report that HEAD compiles warning-free so long as you define
PG_PRINTF_ATTRIBUTE to "__syslog__" rather than "gnu_printf".

So attached is a proposed patch to make configure check whether %m
works without a warning, and try "__syslog__" if "gnu_printf" does
not work for that.  (I did it in that order so that if NetBSD get
their heads screwed back on straight and stop complaining about
perfectly GNU-compliant code, we'll go back to selecting "gnu_printf".)

Any objections?

			regards, tom lane

Commits

  1. In pg_log_generic(), be more paranoid about preserving errno.

  2. Make src/common/exec.c's error logging less ugly.

  3. Select appropriate PG_PRINTF_ATTRIBUTE for recent NetBSD.

  4. Fix detection of the result type of strerror_r().

  5. Try another way to detect the result type of strerror_r().

  6. Clean up *printf macros to avoid conflict with format archetypes.

  7. Fix link failures due to snprintf/strerror changes.

  8. Implement %m in src/port/snprintf.c, and teach elog.c to rely on that.

  9. Always use our own versions of *printf().

  10. Incorporate strerror_r() into src/port/snprintf.c, too.

  11. Convert elog.c's useful_strerror() into a globally-used strerror wrapper.

  12. Revert "Distinguish printf-like functions that support %m from those that don't."

  13. Produce compiler errors if errno is referenced inside elog/ereport calls.

  14. Distinguish printf-like functions that support %m from those that don't.

  15. Fix unportable usage of printf("%m").

  16. Be more robust when strerror() doesn't give a useful result.