Synopsis

Throw of NULL integer constant

Enabled by default

Yes

Severity/Certainty

Medium/Medium

Full description

throw(NULL) (equivalent to throw(0)) is never a throw of the null-pointer-constant, which means it can only be caught by an integer handler. This might be undesired behavior, especially if your application only has handlers for pointer-to-type exceptions. This check is identical to MISRAC++2008-15-1-2.

Coding standards

Code examples

The following code example fails the check and will give a warning:

typedef int int32_t;
typedef signed char char_t;
#define	NULL 0

void example(void)
{
  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
    // ...
  }
}

The following code example passes the check and will not give a warning about this issue:

typedef int int32_t;
typedef	signed char char_t;
#define	NULL 0

void example(void)
{
  char_t * p = NULL;
  try {
    throw ( p );             // Compliant
  }
  catch ( int32_t i ) {
    // ...
  }
  catch ( const char_t * ) { // Exception handled here
    // ...
  }
}