php手册 杂项函数大全（解析）

switch(connection_status())
{
case CONNECTION_NORMAL:
   $txt = 'Connection is in a normal state';//连接运行正常
   break;
case CONNECTION_ABORTED:
   $txt = 'Connection aborted';//连接由用户或网络错误终止
   break;
case CONNECTION_TIMEOUT:
   $txt = 'Connection timed out';// 连接超时
   break;
case (CONNECTION_ABORTED & CONNECTION_TIMEOUT):
   $txt = 'Connection aborted and timed out';
   break;
default:
   $txt = 'Unknown';//未知错误
   break;
}

echo $txt;

define("GREETING","Hello world!");//定义常量
echo constant("GREETING");//输出常量

define("GREETING","Hello world!",true);//定义常量,不区分大小写
echo constant("greeting");//输出常量

define("GREETING","Hello world!");
echo defined("GREETING");//判断常量是否存在

$site = "666";
fopen($site,"r")
or die("Unable to connect to $site");//输出信息，并推出当前程序
echo "66666448";
?>

$string = "beautiful";
$time = "winter";

$str = 'This is a $string $time morning!';
echo $str. "
";
eval("\$str=\"$str\";");//必须以分号;结束，不然会报错
echo $str;

$site="6666";
fopen($site,"r")
or exit("Unable to connect to $site");

echo $_SERVER['HTTP_USER_AGENT'];
$browser=get_browser(null,true);//返回浏览器的性能
print_r($browser);

echo date('h:i:s');
sleep(10);
echo "
";//耐心等十秒
echo date('h:i:s');

echo uniqid();//刷新都会变.以微秒计的当前时间，生成一个唯一的 ID。

echo date('h:i:s') . "
";

//延迟 10 描述
usleep(10000000);//一微秒等于百万分之一秒。

//再次开始
echo date('h:i:s');
?>