The Old New Thing

Practical development throughout the evolution of Windows.

Latest posts

How can I detect if one of my helper processes is launching child processes?
May 23, 2025
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How can I detect if one of my helper processes is launching child processes?

Raymond Chen
Raymond Chen

You can ask a job object to keep track for you.

How can I create a window the size of the screen without it being treated as a fullscreen window?
May 22, 2025
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How can I create a window the size of the screen without it being treated as a fullscreen window?

Raymond Chen
Raymond Chen

You can declare that you aren't rude.

Silly parlor tricks: Promoting a 32-bit value to a 64-bit value when you don’t care about garbage in the upper bits
May 21, 2025
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Silly parlor tricks: Promoting a 32-bit value to a 64-bit value when you don’t care about garbage in the upper bits

Raymond Chen
Raymond Chen

Inline assembly that doesn't do anything.

Why does Windows report my processor speed twice, with slightly different values?
May 20, 2025
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Why does Windows report my processor speed twice, with slightly different values?

Raymond Chen
Raymond Chen

One is calculated. The other is self-promotion.

Secret passages on Microsoft main campus, episode 3
May 19, 2025
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Secret passages on Microsoft main campus, episode 3

Raymond Chen
Raymond Chen

Another covered passage between buildings.

What’s with the weird <CODE>wReserved</CODE> value at the start of the <CODE>DECIMAL</CODE> structure?
May 16, 2025
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What’s with the weird wReserved value at the start of the DECIMAL structure?

Raymond Chen
Raymond Chen

It's where the discriminant goes when the DECIMAL is put "inside" a VARIANT.

How do I force RunOnce commands to run in a specific order?
May 15, 2025
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How do I force RunOnce commands to run in a specific order?

Raymond Chen
Raymond Chen

Run them in the desired order yourself.

If I mark my thread pool callback as long-running, does it still count toward the thread pool thread limit?
May 14, 2025
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If I mark my thread pool callback as long-running, does it still count toward the thread pool thread limit?

Raymond Chen
Raymond Chen

Yes, because it's still in the thread pool.

What is the developer set-up for developing Windows for multiple processor architectures?
May 13, 2025
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What is the developer set-up for developing Windows for multiple processor architectures?

Raymond Chen
Raymond Chen

You usually just pick one and count on your friends for the others.