Re: Add errdetail() with PID and UID about source of termination signal

> On Apr 9, 2026, at 22:47, Andres Freund <andres@anarazel.de> wrote:
> 
> Hi,
> 
> On 2026-04-09 14:14:23 +0800, Chao Li wrote:
>>> For uid, 0 is usually a valid value for root. So using 0 as the “unknown” value seems a bit awkward. Maybe we should instead document something like "uid is only meaningful when pid is not 0".
>>> 
>> 
>> Forgot to mention, I got a lot of compile warnings, for example:
>> ```
>> parallel.c:1052:20: warning: cast from 'void (*)(int)' to 'pqsigfunc' (aka 'void (*)(int, struct pg_signal_info *)') converts to incompatible function type [-Wcast-function-type-mismatch]
>> 1052 |         pqsignal(SIGPIPE, PG_SIG_IGN);
>>      |                           ^~~~~~~~~~
>> ../../../src/include/port.h:551:20: note: expanded from macro 'PG_SIG_IGN'
>>  551 | #define PG_SIG_IGN (pqsigfunc) SIG_IGN
>>      |                    ^~~~~~~~~~~~~~~~~~~
>> 4 warnings generated.
>> ```
> 
> That's an annoying warning, GAH. Can't imagine this is the only thing it
> complains about. Yes, compiler, I put a cast there, because I did actually
> want to cast, thanks.
> 
> I guess we'll have to define PG_SIG_IGN to 1 and PG_SIG_DFL to 0 ourselves.
> 
> Greetings,
> 
> Andres Freund

I think PG already has pg_funcptr_t to treat this case, this change eliminates the warnings for me:
```
chaol@ChaodeMacBook-Air postgresql % git diff
diff --git a/src/include/port.h b/src/include/port.h
index 7db476d7b01..c029878c6be 100644
--- a/src/include/port.h
+++ b/src/include/port.h
@@ -547,8 +547,8 @@ extern int  pg_mkdir_p(char *path, int omode);
 #define pqsignal pqsignal_be
 #endif

-#define PG_SIG_DFL (pqsigfunc) SIG_DFL
-#define PG_SIG_IGN (pqsigfunc) SIG_IGN
+#define PG_SIG_DFL (pqsigfunc) (pg_funcptr_t) SIG_DFL
+#define PG_SIG_IGN (pqsigfunc) (pg_funcptr_t) SIG_IGN
 typedef void (*pqsigfunc) (SIGNAL_ARGS);
 extern void pqsignal(int signo, pqsigfunc func);
```

Best regards,
--
Chao Li (Evan)
HighGo Software Co., Ltd.
https://www.highgo.com/