On Fri, 6 Oct 2023, Timur Doumler via Liaison wrote:

> I'm not sure if the term "odr-use" makes any sense in C but I hope you
> still know what I mean.

C has the rules in 6.9 about when an identifier with external linkage used
outside certain limited contexts (that are obviously unevaluated) must be
defined somewhere in the program, and similarly requiring any identifier
with internal linkage used outside those contexts to be defined in the
translation unit.

-- 
Joseph S. Myers
joseph_at_[hidden]