diff --git a/src/include/iocompat.h b/src/include/iocompat.h
index e44600d7e..20df2fc28 100644
--- a/src/include/iocompat.h
+++ b/src/include/iocompat.h
@@ -48,7 +48,7 @@
 #define R_OK	1	// FIXME: correct?
 #else
 #define R_OK	4
-#define F_OK	4
+#define F_OK	0
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <direct.h>