Michael Paquier <michael@paquier.xyz> writes: > On Fri, Nov 27, 2020 at 04:10:27PM +0530, Ashutosh Bapat wrote: >> Off list Craig Ringer suggested introducing a new format specifier >> similar to %m for LSN but I did not get time to take a look at the >> relevant code. AFAIU it's available only to elog/ereport, so may not >> be useful generally. But teaching printf variants about the new format >> would be the best solution. However, I didn't find any way to do that.
> -1. %m maps to errno, that is much more generic. A set of macros > that maps to our internal format would be fine enough IMO.
Agreed. snprintf.c is meant to implement a recognized standard (ok, %m is a GNU extension, but it's still pretty standard). I'm not on board with putting PG-only extensions in there.
Fair enough. I did not realise that %m was a GNU extension (never looked closely) so I thought we had precedent for Pg specific extensions there.
