Showing tag results for Code

An operation is "thread-safe" if it can be performed from multiple threads safely, even if the calls happen simultaneously on multiple threads. An operation is re-entrant if it can be performed while the operation is already in progress (perhaps in another context). This is a stronger concept than thread-safety, because the second attempt to per...

The SHLoadInProc function instructs Explorer to create an instance of a particular CLSID. This causes the DLL responsible for that CLSID to be loaded. But when is it unloaded? This is one of those puzzles you should be able to figure out by thinking about it. Consider: The object is created by calling CoCreateInstance and then imme...

Regional windows are neat, but they come at a cost. Most of the cost you can see directly. For example, constantly changing the region clearly generates a cost since you have to sit there and generate new regions all the time. One question that came up on an internal performance alias highlights one of the hidden costs of regional windows: The p...

Just a little tip: If you're going to be adding a lot of items to a listbox or combobox, there are a few little things you can do to improve the performance significantly. (Note: The improvements work only if you have a lot of items, like hundreds. Of course, the usability of a listbox with a hundred items is questionable, but I'm assuming you h...

Everybody who has messed with window messaging knows that GetMessage and PeekMessage retrieve queued messages, which are dispatched to windows via DispatchMessage. Most people also know that GetMessage and PeekMessage will also dispatch nonqueued messages. (All pending nonqueued messages are dispatched, then the first queued message is retur...

What happens when you delete a file while it is open?

Sometimes you might want to determine whether you can do something without actually doing it. For example, you might want to know whether you have a particular permission in a directory, say permission to delete files from it. One way is to retrieve the ACL and then check whether the current user has the desired permission. The AccessCheck functio...

One of the flags you can pass to the SHGetFileInfo function is SHGFI_USEFILEATTRIBUTES. What does this flag mean? It means, "Do not access the disk. Pretend that the file/directory exists, and that its file attributes are what I passed as the dwFileAttributes parameter. Do this regardless of whether it actually exists or not." You can ...

Among other things, you need to understand weak memory models. Hereby incorporating by reference Brad Abrams' discussion of volatile and MemoryBarrier(). In particular, Vance Morrison's discussion of memory models is important reading. (Though I think Brad is being too pessimistic about volatile. Ensuring release semantics at the stor...

In a comment, Darrell Norton asked for a "View in Mozilla" option for Internet Explorer. You can already do this. Internet Explorer's context menu extension mechanism has been in MSDN for years. Let me show you how you can create this extension yourself. First, create the following registry key: Of course, you need to change C:\some\pa...