Update Walkthrough Creating traditional Windows Desktop Apps.

[thispsj]

This PR updates this article on ms docs. The code has been updated to use CreateWindowEx.

[ghost]

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[thispsj]

@corob-msft any problems with the PR ?

[colin-home]

@thispsj
Thanks for bringing this sample from the late '80s into the early '90s. I've been vacationing and not paying close attention to the repo. Your changes are mostly fine, though I don't see much value in changing the wcex.hIcon load from using the parameter hInstance to using the copy in the struct. In optimized code, the value is enregistered at that point, so it makes no difference, while in debug code it could conceivably cause an extra memory access. (I haven't checked the assembly output to verify.) Did you have a purpose or style guideline in mind for that change?

[thispsj]

@corob-msft Here are the assembly output for both cases in debug mode.

This is one of my small projects which uses WCNDCLASSEX structure to create the window. Here the variable assigned to the structure is wcx and not wcex. That's the only difference in the cpp code.
As you see in the assembly, the mov instruction directly registers the pointer to hInst (the HINSTANCE variable) when directly passed while when wcex.hInstance is used it passes that pointer. Otherwise it's the same.

And one more thing, the sample code is itself using wcex.hInstance to load the small icon. So, to my main purpose was to use the same logic as applicable everywhere because I've seen people asking that why is it different in the same code (i.e. at one place hInst and at the another wcex.hInstance.

And sorry if I've bothered you in the middle of your vacation. I hope you won't mind that and continue enjoying your vacation. Summer is the best time to vacation after all.

[colin-home]

Looks good, @thispsj - thanks for the update.