Why is there no way to add a permission to a page with VirtualProtect instead of replacing it?

Raymond ChenNovember 16, 2017Nov 16, 201711/16/17

The Virtual­Protect function lets you change the protection of a page, but all it can do is replace the current protections with the protections you specify, returning the old protections. There is no way to add a protection to a page. In other words, there is an Interlocked­Exchange for page protections, but no Interlocked­Or. Why...

What happens if you simply return from the thread callback passed to _beginthread and _beginthreadex?

Raymond ChenNovember 15, 2017Nov 15, 201711/15/17

Medinoc asks, "What happens when one simply returns from the thread callback? I'd suspect the code gluing between _beginthread() and its callback calls _endthread() upon return, while the code between _beginthreadex() and its callback calls _endthreadex() instead?" Yup, that's exactly it. If your thread callback function returns, then _begin&...

Cancelling the INamespace­Walk::Walk operation a little faster

Raymond ChenNovember 10, 2017Nov 10, 201711/10/17

We saw last time that you can stop a INamespace­Walk::Walk operation by returning a COM error code from the Enter­Folder or Found­Item callback. However, that may not be fast enough. I noted some time ago that if you're going to enumerate the contents of a directory, you'd best do it all at once. And that's what INamespace­...

How can I cancel the INamespace­Walk::Walk operation?

Raymond ChenNovember 9, 2017Nov 9, 201711/9/17

We saw that you can stop a INamespace­Walk::Walk operation by returning a COM error code from the Enter­Folder or Found­Item callback. So let's do that in order to add a timeout to the namespace walk operation. At each callback, we'll check how much time has elapsed since the operation started, and if it's too long, then we return...

How can I control which parts of the shell namespace the INamespaceWalk::Walk operation will walk into?

Raymond ChenNovember 8, 2017Nov 8, 201711/8/17

The INamespace­Walk::Walk method initiates a depth-first traversal of the shell namespace, subject to constraints controlled by the various parameters (such as maximum search depth). If you pass an object which implements the INamespace­Walk­CB interface, you can monitor the progress of the namespace walk and also influence how it ...