Boolean bit-fields are indeed valid. Usual semantics for objects of type
_Bool apply.
C99 6.7.2.1 Structure and union specifiers
4 A bit-field shall have a type that is a qualified or unqualified
version of _Bool, signed int, unsigned int, or some other
implementation-defined type.
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Nick Bowler, Elliptic Semiconductor (http://www.ellipticsemi.com/)
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