Fixing member data type for rect_t to uin32_t as the geometry type in xcb seems to consist of unsigned 32-bit integral numbers.

include/i3ipc++/ipc.hpp

@@ -28,10 +28,10 @@ std::string  get_socketpath();
  * Primitive of rectangle
  */
 struct rect_t {
-	int  x; ///< Position on X axis
-	int  y; ///< Position on Y axis
-	int  width; ///< Width of rectangle
-	int  height; ///< Height of rectangle
+	uint32_t  x; ///< Position on X axis
+	uint32_t  y; ///< Position on Y axis
+	uint32_t  width; ///< Width of rectangle
+	uint32_t  height; ///< Height of rectangle
 };
 
 /**