diff --git a/src/log.cpp b/src/log.cpp
index 9ee61f6..b078986 100644
--- a/src/log.cpp
+++ b/src/log.cpp
@@ -54,7 +54,7 @@ public:
 		: m_writePos(0)
 		, m_readPos(0)
 	{
-		is_main_thread = true;
+		set_main_thread();
 
 		m_logFile.open(log_file_name, std::ios::app | std::ios::binary);
 
diff --git a/src/p2pool.cpp b/src/p2pool.cpp
index b3d7ed9..870c62e 100644
--- a/src/p2pool.cpp
+++ b/src/p2pool.cpp
@@ -226,7 +226,7 @@ void p2pool::handle_miner_data(MinerData& data)
 		"\n---------------------------------------------------------------------------------------------------------------"
 	);
 
-	if (!is_main_thread) {
+	if (!is_main_thread()) {
 		update_block_template_async();
 	}
 	else {
diff --git a/src/util.cpp b/src/util.cpp
index 19f944c..fdc0b72 100644
--- a/src/util.cpp
+++ b/src/util.cpp
@@ -225,7 +225,7 @@ void uv_rwlock_init_checked(uv_rwlock_t* lock)
 
 uv_loop_t* uv_default_loop_checked()
 {
-	if (!is_main_thread) {
+	if (!is_main_thread()) {
 		LOGERR(1, "uv_default_loop() can only be used by the main thread. Fix the code!");
 #ifdef _WIN32
 		if (IsDebuggerPresent()) {
@@ -339,7 +339,10 @@ void BackgroundJobTracker::print_status()
 }
 
 BackgroundJobTracker bkg_jobs_tracker;
-thread_local bool is_main_thread = false;
+
+static thread_local bool main_thread = false;
+void set_main_thread() { main_thread = true; }
+bool is_main_thread() { return main_thread; }
 
 bool resolve_host(std::string& host, bool& is_v6)
 {
diff --git a/src/util.h b/src/util.h
index 073a351..74f2f2a 100644
--- a/src/util.h
+++ b/src/util.h
@@ -133,7 +133,9 @@ private:
 };
 
 extern BackgroundJobTracker bkg_jobs_tracker;
-extern thread_local bool is_main_thread;
+
+void set_main_thread();
+bool is_main_thread();
 
 bool resolve_host(std::string& host, bool& is_v6);