[previous] 2911 [next] Definite: Wraparound in unsigned arithmetic operation.
Overflow and wraparound

An arithmetic operation is being performed in an unsigned type. Examination of the context indicates that the result is always too large to be representable in this type and so wraparound will occur - the result will be truncated using modulo arithmetic. Perhaps this is intended ?

For example: 


/*PRQA S 1278,2017,2982,2983,2984,2986,3120,3198,3199,3203,3227,3372,3408 ++*/
/*******************************/
/* OPTIONS: -s int=16          */
/*******************************/
void foo(unsigned int un)
{
    unsigned unr;

    if (un > 40000U)
    {
        unr = un * 7U;              /* 2911 */
        unr = un + un;              /* 2911 */
    }
    else
    {
        unr = un - 50000U;          /* 2911 */
    }
}

See also:

QA·C Source Code Analyser 8.1.2
© 2013 Programming Research.
www.programmingresearch.com 		Personality Groups | Glossary | Message Index Contents