Showing tag results for Code

Commenter POKE53280,0 claims, "If one validates parameters before using string functions (which quality programmers should do), the 'safe' functions have no reason to exist." Consider the following function: What could possibly go wrong? You check the length of the string, and if it doesn't fit in the buffer, then you reject it. Therefore, y...

One quirk of nested dialogs lies in what happens when the user presses Enter to invoke the default pushbutton: The resulting message goes to the top-level dialog, even if the default pushbutton belongs to a sub-dialog. Why doesn't it send the to the parent of the default pushbutton? I mean, the dialog manager knows the handle of the button, so...

The extended style (known in dialog templates as ) instructs the dialog manager that the dialog's children should be promoted into the dialog's parent. This is easier to explain in pictures than in text. Given the following window hierarchy: The result of the extended style being set is that the children of B are treated as if they were di...

When you build a dialog, either from a template or by explicitly calling , one of the pieces of information about each control is a child window identifier. And it's probably in your best interest to make sure two controls on the dialog don't have the same ID number. Of course, one consequence of giving two control the same ID number is that the ...

Up until Windows XP, applications could intercept the message and tell Windows, "No, don't shut down." If they were polite about it, they would also inform the user which application blocked system shutdown and why. And if they were really polite about it, they would even provide a way for the user to say, "I don't care; shut down anyway." A...

A customer was using memory-mapped files and installed an exception handler to log in-page errors in the memory-mapped file region. They wanted to know how they could obtain the real disk error that resulted in the memory manager not being able to page-in the requested data. Finding the answer isn't that hard. A quick search for reveals that ...

Many window manager operations are recursive, and eventually the window manager will simply say that enough is enough when the recursion goes too deep. We've seen this when you nest windows more than 50 levels deep or nest menus more than 25 levels deep, for example. (Note also that these limits may change in the future, so don't rely on being a...

Commenter kero wants to know why the function hates . (And , and .) Because everybody hates ! (And , and .) We saw earlier that these class styles violate widely-held assumptions about how drawing works. I mean, who would have thought that asking for two device contexts would give you the same one back twice? Or that changes to one device cont...

A customer created a memory mapping on a large file and found that when the memory manager wanted to page in data from that file, it did so in 32KB chunks. The customer wanted to know if there was a way to increase the chunk size for efficiency. The memory manager decides the chunk size for memory-mapped files, and the chunk size is currently set ...

A customer discovered a bug in their code and wanted some information on how serious it was, so they could assess how urgently they need to issue a fix. We have code that calls with a valid window handle, but then we destroy the window before we get around to calling . When we finally do call , we do so with a window handle. The calls are proba...