Returns: If a read position is available, returns egptr() - gptr().

Returns: If that function returns traits​::​eof(), returns traits​::​eof().

Otherwise, returns sgetc().

Effects: If the input sequence read position is not available, returns uflow().

Otherwise, returns traits​::​to_int_type(*gptr()) and increments the next pointer for the input sequence.

Returns: If the input sequence read position is not available, returns underflow().

Otherwise, returns traits​::​to_int_type(*gptr()).

streamsize sgetn(char_type* s, streamsize n);