Question

I want to set anexact client size (say 300 x 300) when I create a normal ‘overlapped’ window.

There is the AdjustWindowRectEx() function where I can pass the desired client
area and get sizes that I can pass to CreateWindowEx but it says
in the documentation that I should not use it for overlapped windows
and I do not understand why.

When I pass 300 x 300, I got 306 x 326 from it, and when I receive
WM_SIZE, the client size is 298 x 298 so it is 2 pixels too small.

How to create overlapped window with exact given client size?

Answer 1

My mistake in my case was the following:

AdjustWindowRectEx(&rect, WS_OVERLAPPEDWINDOW, WS_CLIPSIBLINGS, FALSE, WS_OVERLAPPEDWINDOW);

Changing to this fixes it:

AdjustWindowRectEx(&rect, WS_OVERLAPPEDWINDOW, WS_CLIPSIBLINGS, FALSE, 0);