when the client area is created

[bennyandthejets]

at what stage, or during which message, does the client rectangle become available? ie, when can you call GetClientRect() for the first time?

[novacain]

Not 100% but after WM_CREATE as this is msg is sent after the windows client area has been created but before it is shown on screen.

If you want to manipulate the client area before it is shown try

AdjustWindowRectEx()

to create a window with the desired client rect size (before the window is created or displayed).