3660			Named bit-field consisting of a single bit declared with a signed type.
	Arrays, structures, unions and bit-fields				REFERENCE - ISO:C90-6.5.2.1 Structure and Union Specifiers - Semantics

/*PRQA S 1-9999 ++*/
/*PRQA S 3660, 3665, 0634, 2850 --*/
/**************************************
 * OPTIONS: -bits+
 *************************************/

struct mysignedbit              /* Message 0634 */
{
    signed int b1:1;            /* Message 3660 */
    signed int   :1;            /* Message 3665 */
    int        b2:1;            /* Message 3660 */
    int          :1;            /* Message 3665 */
};
extern void foo(void)
{
    struct mysignedbit b;
    b.b1 =  0;                  /* OK */
    b.b1 = -1;                  /* OK */
    b.b1 =  1;                  /* Message 2850 - value "1" cannot be represented ! */
}

See also:

• 0634 [I] Bit-fields in this struct/union have not been declared explicitly as unsigned or signed.
• 2850 Constant: Implicit conversion to a signed integer type of insufficient size.
• 3665 Unnamed bit-field consisting of a single bit declared with a signed type.