From 11dd17db1799cfc2defe59571b62b628e0a6eee6 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Pa=CC=84vels=20Nadtoc=CC=8Cajevs?=
 <7645683+bruvzg@users.noreply.github.com>
Date: Thu, 12 Mar 2026 11:56:12 +0200
Subject: [PATCH] Improve `OS.is_process_running` error messages.

---
 drivers/unix/os_unix.cpp | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/unix/os_unix.cpp b/drivers/unix/os_unix.cpp
index 6bcda17854..8079490f6f 100644
--- a/drivers/unix/os_unix.cpp
+++ b/drivers/unix/os_unix.cpp
@@ -857,8 +857,8 @@ bool OS_Unix::_check_pid_is_running(const pid_t p_pid, int *r_status) const {
 		// Thread is still running.
 		return true;
 	}
-
-	ERR_FAIL_COND_V_MSG(result != 0, false, vformat("Thread %d exited with errno: %d", (int)p_pid, errno));
+	ERR_FAIL_COND_V_MSG(result != 0 && errno == ECHILD, false, vformat("The process %d does not exist or is not a child of the calling process.", (int)p_pid));
+	ERR_FAIL_COND_V_MSG(result != 0, false, vformat("waitpid for process %d failed with errno: %d", (int)p_pid, errno));
 
 	// Thread exited normally.
 	status = WIFEXITED(status) ? WEXITSTATUS(status) : status;