output function begins execution by constructing an object of class
If this object returns
while converting to a value of type
the function endeavors
to generate the requested output.
If an exception is thrown during output, then
is turned on
(exceptions() & badbit) != 0
then the exception is rethrown.
In any case, the unformatted output function ends by destroying the
sentry object, then, if no exception was thrown, returning the value
specified for the unformatted output function.