From 22c2483afb5377fdd2b907638b272987be72bfe9 Mon Sep 17 00:00:00 2001
From: Yasushi SHOJI <yashi@spacecubics.com>
Date: Mon, 6 Oct 2025 12:48:15 +0900
Subject: [PATCH] posix: Reintroduce legacy time.h and signal.h headers with
 warnings

Commit 5cbb2a421d95 ("posix: switch to using posix_time.h and
posix_signal.h") removed <zephyr/posix/time.h> and <zephyr/posix/signal.h>
in favor of standard <time.h> and <signal.h>.  However, this was a hard
cut-over. Users including the old headers now encounter build errors
without guidance on how to resolve them.

Reintroduce <zephyr/posix/time.h> and <zephyr/posix/signal.h> as stubs
that emit compile-time warnings and include their corresponding standard
headers. This helps users migrate smoothly by providing actionable
diagnostics.

Signed-off-by: Yasushi SHOJI <yashi@spacecubics.com>
---
 include/zephyr/posix/signal.h | 12 ++++++++++++
 include/zephyr/posix/time.h   | 12 ++++++++++++
 2 files changed, 24 insertions(+)
 create mode 100644 include/zephyr/posix/signal.h
 create mode 100644 include/zephyr/posix/time.h

diff --git a/include/zephyr/posix/signal.h b/include/zephyr/posix/signal.h
new file mode 100644
index 0000000000000..7c8a992c12f2d
--- /dev/null
+++ b/include/zephyr/posix/signal.h
@@ -0,0 +1,12 @@
+/*
+ * Copyright (c) 2025 Space Cubics
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+#ifndef ZEPHYR_INCLUDE_POSIX_SIGNAL_H_
+#define ZEPHYR_INCLUDE_POSIX_SIGNAL_H_
+
+# warning "Since Zephyr v4.3, don't use <zephyr/posix/signal.h> directly; include <signal.h> instead."
+#include_next <signal.h>
+
+#endif /* ZEPHYR_INCLUDE_POSIX_SIGNAL_H_ */
diff --git a/include/zephyr/posix/time.h b/include/zephyr/posix/time.h
new file mode 100644
index 0000000000000..a9c76ceaf1822
--- /dev/null
+++ b/include/zephyr/posix/time.h
@@ -0,0 +1,12 @@
+/*
+ * Copyright (c) 2025 Space Cubics
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+#ifndef ZEPHYR_INCLUDE_POSIX_TIME_H_
+#define ZEPHYR_INCLUDE_POSIX_TIME_H_
+
+# warning "Since Zephyr v4.3, don't use <zephyr/posix/time.h> directly; include <time.h> instead."
+#include_next <time.h>
+
+#endif /* ZEPHYR_INCLUDE_POSIX_TIME_H_ */