QA·C Help - 1474

	1474	Object of enum type is being modified with a bitwise compound assignment operator.

Arithmetic type - Enum types		REFERENCE - ISO:C90-6.5.2.2 Enumeration Specifiers

The value of an enum object is being modified using a bitwise compound assignment operator (&=, |= or ^=). This is permitted in the C language but it is dangerous because it could result in the object containing a value which is not a valid member of the enumeration.

For example:


/*PRQA S 2017,2211,2213,3120,3227,3408,3447,3448,3602,4130 ++*/

typedef enum { RED = 2, GREEN = 4, BLUE = 6 } COLOUR;

extern COLOUR col;

extern void foo(int n)
{
    col &= n;                   /* Message 1474 and 1318 */
    col &= 4;                   /* Message 1474 and 1318 */
    col &= GREEN;               /* Message 1474 and 1318 */

    col |= n;                   /* Message 1474 and 1318 */
    col |= 4;                   /* Message 1474 and 1318 */
    col |= GREEN;               /* Message 1474 and 1318 */

    col ^= n;                   /* Message 1474 and 1318 */
    col ^= 4;                   /* Message 1474 and 1318 */
    col ^= GREEN;               /* Message 1474 and 1318 */

    return;
}

See also:

1318 Object of enum type is being modified with a compound assignment operator.
1479 Object of enum type is being modified with an arithmetic compound assignment operator.

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