overflowing bitfields

[.rhavin grobert]

is there any defined behaviour when doing this:

__________________________
// lets assume you defined 'BYTE'
// to whatever is a 8-bit-byte on your sys;-)

struct x {
BYTE nTreeBit : 3;
BYTE nFiveBit : 5;
}

x.nTreeBit = 42;
__________________________


my i assume nFiveBit stayes untouched?

 

[Jack Klein]

is there any defined behaviour when doing this:

__________________________
// lets assume you defined 'BYTE'
// to whatever is a 8-bit-byte on your sys;-)

struct x {
BYTE nTreeBit : 3;
BYTE nFiveBit : 5;
}

x.nTreeBit = 42;
__________________________


my i assume nFiveBit stayes untouched?

Yes, you may. And the value in nTreeBit is implementation-defined.

--
Jack Klein
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[James Kanze]

Yes, you may. And the value in nTreeBit is implementation-defined.

Not if BYTE is an unsigned type. If BYTE is unsigned, nTreeBit
is guaranteed to be 2.