the container and the number of characters requested. Second, if the number of characters to be read is non-zero, you copy that number of characters from the container into the provided buffer and update the current read position. If the number of characters is zero, i.e., if all the characters in the container have already been consumed by previous calls to read (or if the container was empty to begin with), you return <CODE>-1</CODE> to indicate end-of-stream.</P>

<P>You can read from a container_source 