xsgetn(s, count) of the most derived class.
characters from the input sequence and stores them into a character array pointed to by
. The characters are read as if by repeated calls to sbumpc()
. That is, if less than
characters are immediately available, the function calls uflow()
to provide more until traits::eof()
Classes derived from
std::basic_streambuf are permitted to provide more efficient implementations of this function.
|| pointer to the beginning of a char_type array
|| maximum number of characters to write
 Return value
The number of characters successfully read.
The rule about "more efficient implementations" permits bulk I/O without intermediate buffering: that's how std::ifstream::read simply passes the pointer to the POSIX
read() system call in some implementations of iostreams
 See also
|| invokes xsputn() |
(public member function)