Return the number of bytes that are guaranteed that can be read before underflow returns eof. If the object is not in a valid state, -1 will be returned. Note that often, the actual number of bytes that can be read will be much greater than the value returned by this function.
Declared in <bdlde_utf8checkinginstreambufwrapper.h>
virtual
std::streamsize
showmanyc() override;