cpp/utility/stacktrace entry/operator cmp

@1@ Compares and  for equality. Two values are equal if and only if they represent the same stacktrace entry, or both of them are empty.

@2@ Gets the relative order between and  in the unspecified strict total order over all  values which is consistent with the equality relation established by.

Return value
@1@ if two  and  compare equal,  otherwise.

@2@ std if and  compare equal. @@ Otherwise, std if is ordered before  in the strict total order. @@ Otherwise, std (in which case is ordered before  in the strict total order).