# V740. Exception is of the 'int' type because NULL is defined as 0. Keyword 'nullptr' can be used for 'pointer' type exception.

The analyzer detected that an exception of type 'int' will be thrown while the programmer wanted it to be of type 'pointer'.

Consider the following example:

    if (unknown_error)
      throw NULL;

If an unknown error occurs, the programmer wants the program to throw a null pointer. However, they didn't take into account that NULL is actually but an ordinary 0. This is how the NULL macro is defined in C++ programs:

    #define NULL 0

The value '0' is of type 'int', so the exception to be thrown will also be of type 'int'.

We're not concerned with the fact that using pointers for exception throwing is bad and dangerous for now – suppose one really needs to do it exactly that way. Then the fixed version of the code above should look like this:

    if (unknown_error)
      throw nullptr;

Why one shouldn't use pointers when working with exceptions is very well explained in the following book:

Stephen C. Dewhurst. C++ Gotchas. Avoiding Common Problems in Coding and Design. – Addison-Wesley Professional. – 352 pp.: ill., ISBN-10 0321125185.