V2520. MISRA. Every switch-clause should be terminated by an unconditional 'break' or 'throw' statement.

This diagnostic rule is based on the software development guidelines developed by MISRA (Motor Industry Software Reliability Association).

This diagnostic varies for C and C++. Each label of a 'switch' statement should end with a 'break' statement placed outside the condition. In C++, 'throw' can also be the last statement.

Adding the ending statements guarantees that the execution flow will not "fall through" to the next label and also helps avoid mistakes when adding new labels.

The only exception to this rule is a series of empty labels.

Here is an example of code triggering this warning:

void example_1(int cond, int a)
{
  switch (cond)
  {
  case 1:
  case 2:
    break;
  case 3:  // <=
    if (a == 42)
    {
      DoSmth();
    }
  case 4:  // <=
    DoSmth2();
  default: // <=
    ;
  }
}

Fixed code:

void example_1(int cond, int a)
{
  switch (cond)
  {
  case 1:
  case 2:
    break;
  case 3:
    if (a == 42)
    {
       DoSmth();
    }
    break;
  case 4:
    DoSmth2();
    break;
  default:
    /* No action required */ 
    break;
  }
}

Note that labels should not end with a 'return' statement as it violates the rule V2506.

This diagnostic rule is classified as:

Was this page helpful?

Message submitted.

Your message has been sent. We will email you at

If you do not see the email in your inbox, please check if it is filtered to one of the following folders:

• Promotion
• Updates
• Spam

If you can’t find an answer to your question, fill in the form below and our developers will contact you

By clicking this button you agree to our Privacy Policy statement