Subject: [PATCH v3 2/4] compat/mingw: allow sigaction(SIGCHLD)

From: "Carlo Marcelo Arenas Belón via GitGitGadget" <[email-masked]>
Date: Thu, 26 Jun 2025 08:53:06 +0000

From: =?UTF-8?q?Carlo=20Marcelo=20Arenas=20Bel=C3=B3n?= <[email-masked]>

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.

Signed-off-by: Carlo Marcelo Arenas Belón <[email-masked]>
---
 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)
-- 
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