QA·C Help - 2821

	2821	Definite: Arithmetic operation on NULL pointer.

NULL pointers

A definite anomaly has been detected. Examination of the context indicates that this expression will always result in an arithmetic operation involving a null pointer.

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

For example


/*PRQA S 489,508,2017,3205,3408,3673,4600 ++*/
#define NULL (void *)0

void foo(int *q)
{
    int *p;

    if (q == NULL)
    {
        ++q;                /* 2821 */
    }
}

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.
2822 Apparent: Arithmetic operation on NULL pointer.
2823 Suspicious: Arithmetic operation on NULL pointer.
2824 Possible: Arithmetic operation on NULL pointer.

Personality Groups | Glossary | Message Index

Contents