QA·C Help - 2824

	2824	Possible: Arithmetic operation on NULL pointer.

NULL pointers

A possible dataflow condition has been identified.

A null pointer may be assigned or compared, but any attempt to perform arithmetic operations on it will result in undefined behavior. Be aware that the internal representation of a null pointer constant is implementation-defined and may not necessarily be bitwise 0.

For example:


/*PRQA S 489,510,2017,2983,2986,3199,3205,3408,3673,4600 ++*/
#define NULL (void *)0

void foo(int *p, int *q)
{
    p++;                        /* 2824 */ /* p could be a null pointer */

    if (q != NULL)
    {
        ++q;                    /* ...  */ /* q is NOT a null pointer at this point */
    }
}

See also:

2810 Constant: Dereference of NULL pointer.
2811 Definite: Dereference of NULL pointer.
2812 Apparent: Dereference of NULL pointer.
2813 Suspicious: Dereference of NULL pointer.
2814 Possible: Dereference of NULL pointer.
2820 Constant: Arithmetic operation on NULL pointer.
2821 Definite: Arithmetic operation on NULL pointer.
2822 Apparent: Arithmetic operation on NULL pointer.
2823 Suspicious: Arithmetic operation on NULL pointer.

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