Avoiding double-destruction when an object is released
The trick of the artificial reference count.
The trick of the artificial reference count.
If you try to do too much, you can find yourself in trouble.
We concluded last time that we wanted the custom large font to apply only to the columns containing Chinese characters and leave the original font in place for the English columns. We do this by carrying two fonts around, choosing the appropriate one for each column. class RootWindow : public Window { ... private: HWND m_hwndLV; HWND m_hwndEd...
Let's pay a quick visit to our continuing dictionary project. One of the things you may have noticed is that the Chinese characters are unreadably small. Let's fix that by making them larger. class RootWindow : public Window { public: virtual LPCTSTR ClassName() { return TEXT("Scratch"); } static RootWindow *Create(); RootWindow(); ~RootWind...
One of the important distinctions between mutexes and the other synchronization objects is that mutexes have owners. If the thread that owns a mutex exits without releasing the mutex, the mutex is automatically released on the thread's behalf. But if this happens, you're in big trouble. One thing many people gloss over is the WAIT_ABANDONED re...
The FOR command has become the batch language's looping construct. If you ask for help via FOR /? you can see all the ways it has become overloaded. For example, you can read the output of a command by using the for command. FOR /F "tokens=*" %i IN ('ver') DO echo %i The /F switch in conjunction with the single quotation marks indicates that t...
When I described what the HINSTANCE parameter to the function is for, I neglected to mention why the low-level hooks are not injected. But then again, it should be obvious. The low-level hooks let you see input as it arrives at the window manager. At this low level of processing, the window manager hasn't yet decided what window will receive...
For functions that return data, the contents of the output buffer if the function fails are typically left unspecified. If the function fails, callers should assume nothing about the contents. But that doesn't stop them from assuming it anyway. I was reminded of this topic after reading Michael Kaplan's story of one customer who wanted the ou...
On more than one occasion, I've seen someone ask a question like this: I have some procedure that generates strings dynamically, and I want a formula that takes a string and produces a small unique identifer for that string (a hash code), such that two identical strings have the same identifier, and that if two strings are different, then they wi...
Most people probably haven't noticed this, but there was a change to the requirements for file type handlers that arrived with Windows XP SP 2: Paths to programs now must be fully-qualified if they reside in a directory outside of the Windows directory and the System directory. The reason for this is security with a touch of predictabil...