程序执行函数：proc_open的使用

参考手册，执行一个命令打开input/output文件指针。
array("pipe", "r"),  // stdin is a pipe that the child will read from
   1 => array("pipe", "w"),  // stdout is a pipe that the child will write to
   2 => array("file", "c:        emperror-output.txt", "a") // stderr is a file to write to
);
$cwd = 'c:php';
$env = array('name' => 'liuyiwei');
$process = proc_open('php.exe', $descriptorspec, $pipes, $cwd, $env);
if (is_resource($process)) {
    // $pipes now looks like this:
    // 0 => writeable handle connected to child stdin
    // 1 => readable handle connected to child stdout
    // Any error output will be appended to /tmp/error-output.txt
    fwrite($pipes[0], '');
    fclose($pipes[0]);
    //echo stream_get_contents($pipes[1]);
    //fclose($pipes[1]);
    echo "";
    print_r(proc_get_status($process));
    echo "";
    // It is important that you close any pipes before calling
    // proc_close in order to avoid a deadlock
    //$return_value = proc_close($process);
    //echo "
command returned $return_value
";
}
?>