Is Checking `this == nullptr` Within Member Functions Ever Justifiable?

Is Checking for this == nullptr in Member Functions Ever Justifiable?

In coding, it's common practice to check for nullptr before performing operations on a pointer. But what about member functions? Does it make sense to perform the check this == nullptr within a class method?

Answer:

According to the C standard, calling a method on a null pointer always results in undefined behavior. Checking this == nullptr is therefore redundant and does not guarantee any specific execution path.

However, this practice is sometimes used as a debugging aid or for error handling purposes in specific environments. For example, in VC and MFC, if (this == NULL) checks are present to mitigate issues with non-virtual functions.

Although this == nullptr checks may seem intuitive, relying on them is not recommended. They can create a false sense of security and non-standard behavior across different platforms. For debugging and error handling, assert statements or other appropriate measures should be employed instead.

Additional Considerations:

In multithreaded environments, it's crucial to note that while the check this == nullptr may pass initially, there is no guarantee that the object won't be deleted while the method is executing. This could lead to unexpected behavior or crashes.

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