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A null pointer is usually represented as a pointer to address 0 in the address space; many operating systems set up the MMU to indicate that the page that contains that address is not in memory, and do not include that page in the virtual address space, so that attempts to read or write the memory referenced by a null pointer get an invalid ...
In computer programming, a weak reference is a reference that does not protect the referenced object from collection by a garbage collector, unlike a strong reference.An object referenced only by weak references – meaning "every chain of references that reaches the object includes at least one weak reference as a link" – is considered weakly reachable, and can be treated as unreachable and ...
For example, if the pointer is used to make a virtual function call, a different address (possibly pointing at exploit code) may be called due to the vtable pointer being overwritten. Alternatively, if the pointer is used for writing to memory, some other data structure may be corrupted.
In computer science, a memory leak is a type of resource leak that occurs when a computer program incorrectly manages memory allocations [1] in a way that memory which is no longer needed is not released. A memory leak may also happen when an object is stored in memory but cannot be accessed by the running code (i.e. unreachable memory). [2]
Using non-owned memory: It is common to use pointers to access and modify memory. If such a pointer is a null pointer, dangling pointer (pointing to memory that has already been freed), or to a memory location outside of current stack or heap bounds, it is referring to memory that is not then possessed by the program. Using such pointers is a ...
Often, bugs come about during coding, but faulty design documentation may cause a bug. In some cases, changes to the code may eliminate the problem even though the code then no longer matches the documentation. In an embedded system, the software is often modified to work around a hardware bug since it's cheaper than modifying the hardware.
The original form of the pattern, appearing in Pattern Languages of Program Design 3, [2] has data races, depending on the memory model in use, and it is hard to get right. Some consider it to be an anti-pattern. [3] There are valid forms of the pattern, including the use of the volatile keyword in Java and explicit memory barriers in C++. [4]
For example, a plugin that is running inside another application is expected to handle all errors and exceptions in such a way as to not crash the application in which it is embedded. Blanket catching of errors and exceptions is a pattern that is easy to fall into when attempting to prevent crashes at all costs, and when you combine that with ...