From: Gerhard Sittig <redacted>
Date: Tue, 18 Sep 2018 16:34:42 +0000 (+0200)
Subject: Logging: avoid "cb was NULL" warning message during logging shutdown
X-Git-Url: https://sigrok.org/gitaction?a=commitdiff_plain;h=e431acda693abc3d0cd339f95a95220c02ae13bd;p=pulseview.git

Logging: avoid "cb was NULL" warning message during logging shutdown

Commit 4b9234088f56 introduced the fetch and restore of the libraries'
default log routines in addition to the registration of a Pulseview
application's log routine. Some code paths in main() could result in
unexpected "cb was NULL" messages on stderr, when logging::init() did
not execute but the destructor tried to restore a handler which was not
fetched before. Silence the error message.
---

diff --git a/pv/logging.cpp b/pv/logging.cpp
index 377011b6..29d023c0 100644
--- a/pv/logging.cpp
+++ b/pv/logging.cpp
@@ -52,11 +52,13 @@ static void *prev_srd_log_cb_data;
 Logging::~Logging()
 {
 	qInstallMessageHandler(nullptr);
-	sr_log_callback_set(prev_sr_log_cb, prev_sr_log_cb_data);
+	if (prev_sr_log_cb)
+		sr_log_callback_set(prev_sr_log_cb, prev_sr_log_cb_data);
 	prev_sr_log_cb = nullptr;
 	prev_sr_log_cb_data = nullptr;
 #ifdef ENABLE_DECODE
-	srd_log_callback_set(prev_srd_log_cb, prev_srd_log_cb_data);
+	if (prev_srd_log_cb)
+		srd_log_callback_set(prev_srd_log_cb, prev_srd_log_cb_data);
 	prev_srd_log_cb = nullptr;
 	prev_srd_log_cb_data = nullptr;
 #endif