Why is accessing "this" after "delete this" in C strictly prohibited?

Beware the Undefined Consequences of "delete this"; Examining Its Value is Prohibited

When using the "delete this" construct in C , the C FAQ strongly advises against attempting to access or manipulate the "this" pointer afterward. The reasons for this restriction extend beyond the previous three outlined in the FAQ:

Reason for Restriction #4: The value of "this" after calling "delete this" is inherently unspecified and undefined. As such, any subsequent attempts to interact with it, including but not limited to the following, are guaranteed to invoke undefined behavior:

• Examination or Inspection
• Comparison with Other Pointers or NULL
• Printing or Outputting its Value
• Reinterpretation Casting
• Any Form of Manipulation

Potential Consequences of Ignoring the Restriction:

While some compilers may handle undefined behavior in this specific instance in a predictable manner, there is no guarantee. The C specification explicitly allows for the compiler to determine any behavior when engaging in undefined actions. This could result in bizarre or even catastrophic consequences, including but not limited to data corruption or complete system failure.

Safe Alternative:

To work around this restriction, it is recommended to create a copy of the "this" pointer (e.g., as an integer) before calling "delete this," ensuring that the original pointer's value remains accessible and predictable after deletion.

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