C11 §6.7.2.1: "The order of allocation of bit-fields within a unit (high-order to low-order or low-order to high-order) is implementation-defined. The alignment

C11 §6.7.2.1: "The order of allocation of bit-fields within a unit (high-order to low-order or low-order to high-order) is implementation-defined. The alignment of the addressable storage unit is unspecified." This makes bitfields quite difficult to use correctly when portability is of interest. It's often easier to write a couple inline get/set functions and use bit indices. If portability isn't a concern, then sure, have at it.