Set lhs to refer to the stop state (or lack thereof) that rhs referred to, and vice versa. Implementation note: this function is required by the standard to be a hidden friend ([hidden.friends], [stoptoken.general]).
lhs
rhs
Declared in <bslstl_stoptoken.h>
<bslstl_stoptoken.h>
void swap( stop_token& lhs, stop_token& rhs) noexcept;