diff --git a/src/posix/cocoa/i_joystick.cpp b/src/posix/cocoa/i_joystick.cpp
index 9b9487cf6..c4bcc85c3 100644
--- a/src/posix/cocoa/i_joystick.cpp
+++ b/src/posix/cocoa/i_joystick.cpp
@@ -157,8 +157,9 @@ private:
 		IOHIDElementCookie cookie;
 		int32_t            value;
 
-		DigitalButton(const IOHIDElementCookie cookie)
+		explicit DigitalButton(const IOHIDElementCookie cookie)
 		: cookie(cookie)
+		, value(0)
 		{ }
 	};