Windows and Messages

The following sections describe the elements of an application with a Windows-based graphical user interface.

In This Section


Discusses windows in general.

Window Classes

Describes the types of window classes, how the system locates them, and the elements that define the default behavior of windows that belong to them.

Window Procedures

Discusses window procedures. Every window has an associated window procedure that processes all messages sent or posted to all windows of the class.

Messages and Message Queues

Describes messages and message queues and how to use them in your applications.


Discusses timers. A timer is an internal routine that repeatedly measures a specified interval, in milliseconds.

Window Properties

Discusses window properties. A window property is any data assigned to a window.


Describes the functions that can be used to control the configuration of system metrics and various system attributes such as double-click time, screen saver time-out, window border width, and desktop pattern.


Discusses hooks. A hook is a point in the system message-handling mechanism where an application can install a subroutine to monitor the message traffic.

Multiple Document Interface

Discusses the Multiple Document Interface which is a specification that defines a user interface for applications that enable the user to work with more than one document at the same time.