From: Phillip Wood <phillip.wood123@gmail.com>
Date: Thu, 26 Jun 2025 12:52:47 GMT
Subject: Re: [PATCH v3 2/4] compat/mingw: allow sigaction(SIGCHLD)
Message-ID: <49cf7749-fc86-4829-8e94-c1f1e87803aa@gmail.com>
In-Reply-To: <3f63479119ffe6fdcf694dac3cb47cd7838564b7.1750927989.git.gitgitgadget@gmail.com>

On 26/06/2025 09:53, Carlo Marcelo Arenas Belón via GitGitGadget wrote:
> From: =?UTF-8?q?Carlo=20Marcelo=20Arenas=20Bel=C3=B3n?= <carenas@gmail.com>
> 
> A future change will start using sigaction to setup a SIGCHLD signal
> handler.
> 
> The current code uses signal() which returns SIG_ERR (but doesn't
> seem to set errno) so instruct sigaction() to do the same.

Why are we returning -1 below instead of SIG_ERR if we want the behavior 
to match?

Thanks

Phillip

> 
> Signed-off-by: Carlo Marcelo Arenas Belón <carenas@gmail.com>
> ---
>   compat/mingw-posix.h | 1 +
>   compat/mingw.c       | 4 +++-
>   2 files changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/compat/mingw-posix.h b/compat/mingw-posix.h
> index a0dca756d104..847d558c9b2d 100644
> --- a/compat/mingw-posix.h
> +++ b/compat/mingw-posix.h
> @@ -95,6 +95,7 @@ struct sigaction {
>   	sig_handler_t sa_handler;
>   	unsigned sa_flags;
>   };
> +#define SA_NOCLDSTOP 1
>   
>   struct itimerval {
>   	struct timeval it_value, it_interval;
> diff --git a/compat/mingw.c b/compat/mingw.c
> index 8a9972a1ca19..5d69ae32f4b9 100644
> --- a/compat/mingw.c
> +++ b/compat/mingw.c
> @@ -2561,7 +2561,9 @@ int setitimer(int type UNUSED, struct itimerval *in, struct itimerval *out)
>   
>   int sigaction(int sig, struct sigaction *in, struct sigaction *out)
>   {
> -	if (sig != SIGALRM)
> +	if (sig == SIGCHLD)
> +		return -1;
> +	else if (sig != SIGALRM)
>   		return errno = EINVAL,
>   			error("sigaction only implemented for SIGALRM");
>   	if (out)