Do not apply pointer arithmetic to pointers

Pointer arithmetic shall only be applied to pointers that address an array or array element (misra2004_17_1_PointerArithmeticOnNotPointers.rule)


Description:

"Pointer arithmetic shall only be applied to pointers that address an array or array element. Addition and subtraction of integers (including increment and decrement) from pointers that do not point to an array or array element results in undefined behaviour."

Benefits:

Rule makes the code more readable and less confusing.

Example:

void foo( int a[] ) {
   int* p1 = 0;
   int* p2;
   int* p3 = a;

   a++;     // OK
   p1++;    // Violation
   p2 = a;
   p2++;    // OK
   p3++;    // OK
}

Repair:

Do not apply pointer arithmetic to pointers.

References:
MISRA-C:2004 Guidelines for the use of the C language in critical systems

Chapter 6, Section 17
Author
ParaSoft


Tags: Pointer arithmetic, less confusing, more readable