diff --git a/src_main/core/piobject.h b/src_main/core/piobject.h
index 2e1e9207..ae8b4025 100755
--- a/src_main/core/piobject.h
+++ b/src_main/core/piobject.h
@@ -633,12 +633,12 @@ public:
 				if (i.performer) {
 					i.performer->postQueuedEvent(__QueuedEvent(i.slot, i.dest, i.dest_o, sender));
 				} else {
-					bool th = sender->thread_safe_;
-					if (th) i.dest_o->mutex_.lock();
+					bool ts = sender->thread_safe_;
+					if (ts) i.dest_o->mutex_.lock();
 					i.dest_o->emitter_ = sender;
 					((void( *)(void * ))i.slot)(i.dest);
 					i.dest_o->emitter_ = 0;
-					if (th) i.dest_o->mutex_.unlock();
+					if (ts) i.dest_o->mutex_.unlock();
 				}
 #ifdef PIP_CXX11_SUPPORT
 			}
@@ -661,12 +661,13 @@ public:
 					if (i.args_count > 0) vl << PIVariant::fromValue(v0);
 					i.performer->postQueuedEvent(__QueuedEvent(i.slot, i.dest, i.dest_o, sender, vl));
 				} else {
-					if (sender->thread_safe_) i.dest_o->mutex_.lock();
+					bool ts = sender->thread_safe_;
+					if (ts) i.dest_o->mutex_.lock();
 					i.dest_o->emitter_ = sender;
 					if (i.args_count == 0) ((void(*)(void *))i.slot)(i.dest);
 					else ((void(*)(void * , T0))i.slot)(i.dest, v0);
 					i.dest_o->emitter_ = 0;
-					if (sender->thread_safe_) i.dest_o->mutex_.unlock();
+					if (ts) i.dest_o->mutex_.unlock();
 				}
 #ifdef PIP_CXX11_SUPPORT
 			}
@@ -689,7 +690,8 @@ public:
 					if (i.args_count > 1) vl << PIVariant::fromValue(v1);
 					i.performer->postQueuedEvent(__QueuedEvent(i.slot, i.dest, i.dest_o, sender, vl));
 				} else {
-					if (sender->thread_safe_) i.dest_o->mutex_.lock();
+					bool ts = sender->thread_safe_;
+					if (ts) i.dest_o->mutex_.lock();
 					i.dest_o->emitter_ = sender;
 					switch (i.args_count) {
 					case 0: ((void(*)(void *))i.slot)(i.dest); break;
@@ -697,7 +699,7 @@ public:
 					default: ((void(*)(void * , T0, T1))i.slot)(i.dest, v0, v1); break;
 					}
 					i.dest_o->emitter_ = 0;
-					if (sender->thread_safe_) i.dest_o->mutex_.unlock();
+					if (ts) i.dest_o->mutex_.unlock();
 				}
 #ifdef PIP_CXX11_SUPPORT
 			}
@@ -721,7 +723,8 @@ public:
 					if (i.args_count > 2) vl << PIVariant::fromValue(v2);
 					i.performer->postQueuedEvent(__QueuedEvent(i.slot, i.dest, i.dest_o, sender, vl));
 				} else {
-					if (sender->thread_safe_) i.dest_o->mutex_.lock();
+					bool ts = sender->thread_safe_;
+					if (ts) i.dest_o->mutex_.lock();
 					i.dest_o->emitter_ = sender;
 					switch (i.args_count) {
 					case 0: ((void(*)(void *))i.slot)(i.dest); break;
@@ -730,7 +733,7 @@ public:
 					default: ((void(*)(void * , T0, T1, T2))i.slot)(i.dest, v0, v1, v2); break;
 					}
 					i.dest_o->emitter_ = 0;
-					if (sender->thread_safe_) i.dest_o->mutex_.unlock();
+					if (ts) i.dest_o->mutex_.unlock();
 				}
 #ifdef PIP_CXX11_SUPPORT
 			}
@@ -755,7 +758,8 @@ public:
 					if (i.args_count > 3) vl << PIVariant::fromValue(v3);
 					i.performer->postQueuedEvent(__QueuedEvent(i.slot, i.dest, i.dest_o, sender, vl));
 				} else {
-					if (sender->thread_safe_) i.dest_o->mutex_.lock();
+					bool ts = sender->thread_safe_;
+					if (ts) i.dest_o->mutex_.lock();
 					i.dest_o->emitter_ = sender;
 					switch (i.args_count) {
 					case 0: ((void(*)(void *))i.slot)(i.dest); break;
@@ -765,7 +769,7 @@ public:
 					default: ((void(*)(void * , T0, T1, T2, T3))i.slot)(i.dest, v0, v1, v2, v3); break;
 					}
 					i.dest_o->emitter_ = 0;
-					if (sender->thread_safe_) i.dest_o->mutex_.unlock();
+					if (ts) i.dest_o->mutex_.unlock();
 				}
 #ifdef PIP_CXX11_SUPPORT
 			}