@@ -13,10 +13,12 @@
  * Public License, either version 2 or 3, which can be found in the file
  * LICENSE.GPLv2 or LICENSE.GPLv3 respectively included in the packaging of this
  * file.
  */
 
+#include <errno.h>
+
 bool
 of_mutex_new(of_mutex_t *mutex)
 {
 	InitializeCriticalSection(mutex);
 
@@ -32,11 +34,16 @@
 }
 
 bool
 of_mutex_trylock(of_mutex_t *mutex)
 {
-	return TryEnterCriticalSection(mutex);
+	if (!TryEnterCriticalSection(mutex)) {
+		errno = EBUSY;
+		return false;
+	}
+
+	return true;
 }
 
 bool
 of_mutex_unlock(of_mutex_t *mutex)
 {