diff --git a/apps/enclave/libsockthread/src/mutex.cpp b/apps/enclave/libsockthread/src/mutex.cpp
index af50a63432628c9e4d58d4e3dfcbe8dee3a31311..284932cc0bb3a312f18e7c684a88eccef680e895 100644
--- a/apps/enclave/libsockthread/src/mutex.cpp
+++ b/apps/enclave/libsockthread/src/mutex.cpp
@@ -43,7 +43,7 @@ Mutex::Mutex(void)
 	assert(mutex != NULL);
 #else
 	int rc = pthread_mutex_init(&mutex, NULL);
-	assert(!rc);
+	assert(rc == 0);
 #endif
 }
 
@@ -54,10 +54,10 @@ Mutex::~Mutex(void)
 {
 #ifdef WINTHREAD
 	BOOL rc = CloseHandle(mutex);
-	assert(!rc);
+	assert(rc);
 #else
 	int rc = pthread_mutex_destroy(&mutex);
-	assert(!rc);
+	assert(rc == 0);
 #endif
 }
 
@@ -71,7 +71,7 @@ void Mutex::lock(void)
 	assert(rc != WAIT_FAILED);
 #else
 	int rc = pthread_mutex_lock(&mutex);
-	assert(!rc);
+	assert(rc == 0);
 #endif
 }
 
@@ -82,9 +82,9 @@ void Mutex::unlock(void)
 {
 #ifdef WINTHREAD
 	BOOL rc = ReleaseMutex(mutex);
-	assert(!rc);
+	assert(rc);
 #else
 	int rc = pthread_mutex_unlock(&mutex);
-	assert(!rc);
+	assert(rc == 0);
 #endif
 }
diff --git a/apps/enclave/libsockthread/src/thread.cpp b/apps/enclave/libsockthread/src/thread.cpp
index a97774c0518ea53b48d9f8bc21912213964b7ca9..9f0716aa4f97c95dde3f99a0c7cec33773a674ce 100644
--- a/apps/enclave/libsockthread/src/thread.cpp
+++ b/apps/enclave/libsockthread/src/thread.cpp
@@ -75,10 +75,10 @@ void Thread::kill(void)
 #endif
 #ifdef WINTHREAD
 	BOOL rc = TerminateThread(handle, 0);
-	assert(!rc);
+	assert(rc);
 #else
 	int rc = pthread_cancel(id);
-	assert(!rc);
+	assert(rc == 0);
 #endif
 	running = false;
 	running_m.unlock();
@@ -101,7 +101,7 @@ void Thread::start(void)
 	assert(handle != NULL);
 #else
 	int rc = pthread_create(&id, NULL, &the_thread, this);
-	assert(!rc);
+	assert(rc == 0);
 #endif
 	// Wait until `running' is set
 	running_m.lock();