From d060348df07424e0517184fb77bc8e57652bcd85 Mon Sep 17 00:00:00 2001
From: Paul Davis <paul@linuxaudiosystems.com>
Date: Mon, 13 Jun 2022 13:48:37 -0600
Subject: [PATCH] main: add a SIGUSR1 handler to allow dynamic triggering of
 debug bits

---
 gtk2_ardour/main.cc | 29 +++++++++++++++++++++++++++--
 1 file changed, 27 insertions(+), 2 deletions(-)

diff --git a/gtk2_ardour/main.cc b/gtk2_ardour/main.cc
index 43faab8c11..7284a57871 100644
--- a/gtk2_ardour/main.cc
+++ b/gtk2_ardour/main.cc
@@ -173,6 +173,19 @@ Click OK to exit %1."), PROGRAM_NAME, AudioEngine::instance()->current_backend_n
 	return false; /* do not call again */
 }
 
+#ifndef NDEBUG
+static void
+sigusr1_handler (int /* signal */)
+{
+	cerr << "SIGUSR1 received in thread " << pthread_name() << endl;
+	char const * adf = g_getenv ("ARDOUR_DEBUG_FLAGS");
+	if (!adf) {
+		return;
+	}
+	PBD::parse_debug_options (adf);
+}
+#endif
+
 #ifndef PLATFORM_WINDOWS
 static void
 sigpipe_handler (int /*signal*/)
@@ -309,9 +322,11 @@ int main (int argc, char *argv[])
 
 	{
 #ifndef NDEBUG
-		const char *adf;
+		const char * adf;
 		if ((adf = g_getenv ("ARDOUR_DEBUG_FLAGS"))) {
-			PBD::parse_debug_options (adf);
+			if (!g_getenv ("ARDOUR_DEBUG_ON_SIGUSR1")) {
+				PBD::parse_debug_options (adf);
+			}
 		}
 #endif /* NDEBUG */
 	}
@@ -402,6 +417,16 @@ int main (int argc, char *argv[])
 	}
 #endif
 
+#ifndef NDEBUG
+	if (g_getenv ("ARDOUR_DEBUG_ON_SIGUSR1")) {
+		if (::signal (SIGUSR1, sigusr1_handler)) {
+			cerr << _("Cannot install SIGUSR1 error handler") << endl;
+		} else {
+			cerr << _("Installed SIGUSR1 debug handler") << endl;
+		}
+	}
+#endif
+
 	DEBUG_TRACE (DEBUG::Locale, string_compose ("main() locale '%1'\n", setlocale (LC_NUMERIC, NULL)));
 
 	if (UIConfiguration::instance().pre_gui_init ()) {