Re: wait(2) and SIGCHLD

[Johnny Billquist <bqt%softjar.se@localhost>]

I agree that this is confusing. While the system definitely 
differentiates between SIG_DFL and SIG_IGN, the difference would 
normally not be something I expected to make a difference in something 
described the way wait(2) is documented.

I haven't really bothered going down into the code and find the answer, 
but I'm curious what other answers pops up for this one.

  Johnny

On 2020-08-14 13:51, Edgar Fuß wrote:
> I'm confused regarding the behaviour of wait(2) wrt. SIGCHLD handling.
>
> The wait(2) manpage says:
>
> 	wait() will fail and return immediately if:
> 	[ECHILD]	The calling process has no existing unwaited-for child
> 			processes; or no status from the terminated child
> 			process is available because the calling process has
> 			asked the system to discard such status by ignoring
> 			the signal SIGCHLD or setting the flag SA_NOCLDWAIT
> 			for that signal.
>
> However, ignore is the default handler for SIGCHLD.
>
> So does the
> 	because the calling process has asked the system
> 	to discard such status by ignoring the signal SIGCHLD
> mean that explicitly ignoring SIGCHLD is different from ignoring it per default?

--
Johnny Billquist                  || "I'm on a bus
                                  ||  on a psychedelic trip
email: bqt%softjar.se@localhost             ||  Reading murder books
pdp is alive!                     ||  tryin' to stay hip" - B. Idol