# V769. The pointer in the expression equals nullptr. The resulting value is meaningless and should not be used.

The analyzer detected a strange operation involving a null pointer and making the resulting pointer meaningless. Such behavior indicates a logic error.

Consider the following example:

    void foo(bool isEmpty, char *str)
    {
      char *begin = isEmpty ? str : nullptr;
      char *end = begin + strlen(str);
      ....
    }

If the 'begin' pointer equals nullptr, the "nullptr + len" expression does not make sense: you cannot use it anyway. Perhaps the variable will not be used anymore. In that case, the code should be refactored so that this operation is never applied to a null pointer, as the programmer who will be dealing with the code may forget that the variable should not be used and attempt to access the data pointed to by the incorrect pointer, which will lead to errors.

The code above can be modified in the following way:

    void foo(bool isEmpty, char *str)
    {
      char *begin = isEmpty ? str : nullptr;
      if (begin != nullptr)
      {
        char *end = begin + strlen(str);
        ....
      }
      ....
    }

This diagnostic is classified as:

CWE-119 CERT-EXP08-C

You can look at examples of errors detected by the V769 diagnostic.