1 files changed, 1 insertions, 0 deletions

diff --git a/mutex.h b/mutex.h
index 651f0da..7eb89cf 100644
--- a/mutex.h
+++ b/mutex.h
@@ -86,6 +86,7 @@ inline void mutex_destroy(char *lock) {
 #else
 
 #include <semaphore.h>
+#include <errno.h>
 
 #define MUTEX_TYPE sem_t