0558			[C] Right operand of '+=' or '-=' must have integral type when left operand is a pointer.
	Constraint violations				REFERENCE - ISO:C90-6.3.16.2 Compound Assignment - Constraints

/*PRQA S 488,510,3120,3227,3408,3447 ++*/

extern float ft;
extern int * pi;
extern int * pj;

void foo(float dec)
{
    ft += dec;                /* OK */
    pi += 2;                  /* OK */
    pi += dec;                /* Message 0558 */
    pi += pj;                 /* Message 0558 */

    ft -= dec;                /* OK */
    pi -= 2;                  /* OK */
    pi -= dec;                /* Message 0558 */
    pi -= pj;                 /* Message 0558 */
}

See also:

• 0485 [C] Only integral expressions may be added to pointers.
• 0486 [C] Only integral expressions and compatible pointers may be subtracted from pointers.