From 69161a3b65b43c86968b7e5e50ceeddb13642b05 Mon Sep 17 00:00:00 2001
From: Fedor Chelnokov <fedor.chelnokov@meshinspector.com>
Date: Tue, 29 Sep 2026 16:01:25 +0300
Subject: [PATCH] mrviewerpy: atexit handler on macOS ignores a viewer it did
 not launch

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
---
 source/mrviewerpy/MRPythonViewer.cpp | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/source/mrviewerpy/MRPythonViewer.cpp b/source/mrviewerpy/MRPythonViewer.cpp
index f7cbdf4377d2..55ac155f76fe 100644
--- a/source/mrviewerpy/MRPythonViewer.cpp
+++ b/source/mrviewerpy/MRPythonViewer.cpp
@@ -381,6 +381,8 @@ void shutViewerAtExit()
     }
     gViewerFinished.wait_for( std::chrono::seconds( 10 ) ); // a stuck loop must not hold the exit forever
 #else
+    if ( !gLaunchParams ) // the viewer was not launched by this module, e.g. Python embedded in an application
+        return;
     auto& viewer = getViewerInstance();
     if ( viewer.isPreLaunched() )
         postLaunchDefaultViewer( *gLaunchParams, *gLaunchSetup );