virtual int_type uflow();
The protected virtual member function endeavors to extract the current element c
from the input stream, then advance
the current stream position, and return the element as T::
to_int_type
(c)
. It can do so in various ways:
c
as the element stored in the read position and advances the next pointer
for the input buffer. c
. If the function cannot succeed, it returns T::
eof
()
, or throws an exception. Otherwise, it returns the current element c
in the input stream, converted as described above, and advances the next pointer for the input buffer. The default
behavior is to call underflow
()
and, if that function returns T::eof()
, to return T::eof()
. Otherwise, the function
returns the current element c
in the input stream, converted as described above, and advances the next pointer for the
input buffer.