You answered your own question. What garabage'. The general answer is that Microsoft is incompetent when it comes to orderly creation and destruction of objects. They get it wrong with windows, with COM, and with device drivers. There's always some catch where an object is half-created or half-destroyed that requires some roundabout convoluted solution to produce a reliable product.
Results by experimentation are better than just trusting the source, especially since the source is composed by a legion of programmers, and none know all the code. That said:. Can I assume that it will always be the first message? No, since code change between versions of windows, and Microsoft has not documented a message guaranteed to be the first one received. Stack Overflow for Teams — Collaborate and share knowledge with a private group.
Create a free Team What is Teams? Collectives on Stack Overflow. Learn more. Windows API: What is the first message a window is guaranteed to receive? Ask Question. Asked 12 years, 2 months ago. Active 1 year, 6 months ago. Viewed 9k times. So, what is the first message a window is guaranteed to receive? Improve this question. A window class defines a set of behaviors that several windows might have in common. For example, in a group of buttons, each button has a similar behavior when the user clicks the button.
Of course, buttons are not completely identical; each button displays its own text string and has its own screen coordinates. Data that is unique for each window is called instance data. Every window must be associated with a window class, even if your program only ever creates one instance of that class. Rather, it is a data structure used internally by the operating system. Window classes are registered with the system at run time.
Class names are local to the current process, so the name only needs to be unique within the process. However, the standard Windows controls also have classes. A pointer to a null-terminated string or an atom that specifies the class name of the new window. The extended window style for the new window. For a list of possible values, see Extended Window Styles.
Because the lpszClass member can contain a pointer to a local and thus inaccessible atom, do not obtain the class name by using this member. Use the GetClassName function instead. This is demonstrated in the following example:. The winuser. Mixing usage of the encoding-neutral alias with code that not encoding-neutral can lead to mismatches that result in compilation or runtime errors. For more information, see Conventions for Function Prototypes. This describes information about a window that is to be shared between instances of it, like the icon, the cursor, and others.
The members are:. After this structure is initialized, the RegisterClassEx function is called. This causes the window class to be registered with Windows, making it known to the application. It returns 0 on failure. Now that the window class has been registered, we can display the window using CreateWindowEx. The arguments are:. That is what is done in this example. CreateWindowEx returns the handle to the newly created window. If window creation failed, it returned NULL. We then show the window by calling ShowWindow.
The first argument for this function is the handle to the window. The second argument is the show style, which indicates how the window is to be displayed.
Most applications just pass the cmdshow argument passed in WinMain. After the window is shown, it must be updated by a call to UpdateWindow. It causes an update message to be sent to the window. We will learn what this means in another tutorial. Now comes the heart of the application: The message pump.
It pumps messages sent to this application by the operating system, and dispatches the messages to the window procedure.
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