0475			[u] Operand of 'sizeof' is an expression designating a bit-field.
	Implicitly undefined				REFERENCE - ISO:C90-6.3.3.4 The sizeof Operator

• Message 0475 is generated when the operand of the sizeof operator refers to a bit-field and is an expression which is not an lvalue.
• Message 0476 is generated when the operand of the sizeof operator refers to a bit-field and is an expression which is an lvalue.

/*PRQA S 702,2017,3131,3198,3199,3203,3408,3447,3621 ++*/

struct ST
{
    unsigned char uc;
    unsigned int  b1:3;
    unsigned int  b2:7;
};

extern struct ST func(void);
extern struct ST stx;


extern void foo(void)
{
    unsigned long ul;

    ul = sizeof(stx.uc);
    ul = sizeof(stx.b1);                /* Message 0476 */

    ul = sizeof(func().uc);             /* Message      3307 and 3470 */
    ul = sizeof(func().b1);             /* Message 0475 3307 and 3470 */
}

See also:

• 0476 [C] 'sizeof' cannot be applied to a bit-field.
• 3307 The operand of 'sizeof' is an expression with implied side effects, but they will not be evaluated.
• 3470 The operand of 'sizeof' is not an expression which designates either an object or a type.