Physically, yes. The difference is whether you let the compiler generate and hide the shift-and-mask ops, or code them by hand. Normally it is better to leave d

Physically, yes. The difference is whether you let the compiler generate and hide the shift-and-mask ops, or code them by hand. Normally it is better to leave details to the compiler. This is the exception to that rule. A result of people avoiding declaring bit fields in serious use cases has been that compiler vendors didn't worry too much about bitfield codegen bugs. Probably Gcc and Clang are OK on x86, by now. But that does not carry to, e.g., obscure microcontrollers. Heaven help you if your bit field members are supposed to correspond to hardware register sub-fields.