diff --git a/utest.h b/utest.h
index 7f2bcaa..f2d5966 100644
--- a/utest.h
+++ b/utest.h
@@ -62,6 +62,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <errno.h>
 
 #if defined(_MSC_VER)
 #pragma warning(pop)
@@ -911,6 +912,7 @@
     }
 
     ns = utest_ns();
+    errno = 0;
     utest_state.tests[index].func(&result, utest_state.tests[index].index);
     ns = utest_ns() - ns;