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As everyone knows, the Visual C++ runtime marks uninitialized or just freed memory blocks with special non-zero markers. Is there any way to disable this behavior entirely without manually setting all uninitialized memory to zeros? It's causing havoc with my valid not null checks, since 0xFEEEFEEE != 0.
Hrm, perhaps I should explain a bit better. I create and initialize a variable (via new), and that all goes just fine. When I free it (via delete), it sets the pointer to 0xFEEEFEEE instead of NULL. When I insert a proper check for NULL, as all good programs that manage their own memory should, I come up with problems as 0xFEEEFEEE passes a NULL check without problems. Is there any good way, other than manually setting all pointers to NULL when deleting them, to detect when memory has already been freed? I would prefer to not use Boost simply because I don't want the overhead, small though it may be, since that's the only thing I'd be using Boost for.
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Use of uninitialized memory means reading data from the buffer that was allocated but not filled with initial values. The program behavior in this case is considered an error which is quite difficult to detect sometimes.
Visual Studio reports warning C6001 when an uninitialized local variable is used before being assigned a value, which can lead to unpredictable results. This warning may be fixed by adding empty curly braces so that the variable/object is value-initialized (will be all zeros).
The realloc() function changes the size of a dynamically allocated memory object. The initial size bytes of the returned memory object are unchanged, but any newly added space is uninitialized, and its value is indeterminate.
If the pointer contains an uninitialized value, then the value might not point to a valid memory location. This could cause the program to read from or write to unexpected memory locations, leading to a denial of service.
When you create a pointer, explicity initialize it to NULL. Likewise after a delete. Depending on the value of uninitialized data (except in a few specific cases) is asking for trouble.
You can save yourself a lot of headaches by using a smart pointer class (such as boost::shared_ptr) which will automatically deal with whether a pointer is initialized or not.
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