MISRA.THROW.NULL

NULL is thrown explicitly.

MISRA-C++ Rule 15-1-2 (required): NULL shall not be thrown explicitly.

Rationale

'throw(NULL)' (equivalent to 'throw(0)') is never a throw of the null-pointer-constant and so is only ever caught by an integer handler. This may be inconsistent with developer expectations, particularly if the program only has handlers for pointer-to-type exceptions.

Example

try
{
   throw ( NULL );       // Non-compliant
}

catch ( int32_t i )      // NULL exception handled here
{
   // ...
}

catch ( const char_t * ) // Developer may expect it to be caught here
{
   // ...
}

char_t * p = NULL;
try
{
   throw ( static_cast < const char_t * > ( NULL ) ); // Compliant,
                                                      // but breaks
                                                      // Rule 15—0—2
   throw ( p );                                       // Compliant
}

catch ( int32_t i )
{
   // ...
}

catch ( const char_t * )    // Both exceptions handled here
{
   // ...
}

External Guidance

• STIG-ID:APP3120 Application has error handling vulnerabilities