The same section (§6.5.7, p.84) in [the relevant C standard][1] (C99) agrees: "If the value of the right operand is…greater than or equal to the width of the promoted left operand, the behavior is undefined." I *do* want to know which C compiler/host platform gives nonzero for the case of shift width equal to word width, though. :) [1]: https://sqlite.org/qmplan.html#software_development_environment