(no version information, might be only in CVS)
php_stream_passthru() outputs
all remaining data from
stream to the active output buffer and returns the
number of bytes output. If buffering is disabled, the data is
written straight to the output, which is the browser making
the request in the case of PHP on a web server, or stdout for
CLI based PHP. This function will use memory mapped files if
possible to help improve performance.