function getstatus($arg){
  print_r(connection_status());
  debug_print_backtrace();
}
reigster_tick_function("getstatus", true);
declare(ticks=1){
  for($i =1; $i<999; $i++){
 echo "hello";
 }
}
unregister_tick_function("getstatus");

這個就基本相當(dāng)于：

function getstatus($arg){
  print_r(connection_status());
  debug_print_backtrace();
}
reigster_tick_function("getstatus", true);
declare(ticks=1){
  for($i =1; $i<999; $i++){
 echo "hello"; getstatus(true);
 }
}
unregister_tick_function("getstatus");

消息，我現(xiàn)在用一個例子來說明，如何結(jié)合ticks來實(shí)現(xiàn)php的消息通信。

$mesg_key = ftok(__file__, 'm');
$mesg_id = msg_get_queue($mesg_key, 0666);
function fetchmessage($mesg_id){
 if(!is_resource($mesg_id)){
  print_r("mesg queue is not ready");
 }
 if(msg_receive($mesg_id, 0, $mesg_type, 1024, $mesg, false, msg_ipc_nowait)){
  print_r("process got a new incoming msg: $mesg ");
 }
}
register_tick_function("fetchmessage", $mesg_id);
declare(ticks=2){
 $i = 0;
 while(++$i < 100){
  if($i%5 == 0){
msg_send($mesg_id, 1, "hi: now index is :". $i);
  }
 }
}
//msg_remove_queue($mesg_id);

在這個例子中，首先將我們的php執(zhí)行process加入到一個由ftok生成的key所獲得的消息隊(duì)列中。

然后，通過ticks，沒隔倆個語句，就去查詢一次消息隊(duì)列。

然后模擬了消息發(fā)送。

在瀏覽器訪問這個腳本，結(jié)果如下：

process got a new incoming msg: s:19:"hi: now index is :5";
process got a new incoming msg: s:20:"hi: now index is :10";
process got a new incoming msg: s:20:"hi: now index is :15";
process got a new incoming msg: s:20:"hi: now index is :20";
process got a new incoming msg: s:20:"hi: now index is :25";
process got a new incoming msg: s:20:"hi: now index is :30";
process got a new incoming msg: s:20:"hi: now index is :35";
process got a new incoming msg: s:20:"hi: now index is :40";
process got a new incoming msg: s:20:"hi: now index is :45";
process got a new incoming msg: s:20:"hi: now index is :50";
process got a new incoming msg: s:20:"hi: now index is :55";
process got a new incoming msg: s:20:"hi: now index is :60";
process got a new incoming msg: s:20:"hi: now index is :65";
process got a new incoming msg: s:20:"hi: now index is :70";
process got a new incoming msg: s:20:"hi: now index is :75";
process got a new incoming msg: s:20:"hi: now index is :80";
process got a new incoming msg: s:20:"hi: now index is :85";
process got a new incoming msg: s:20:"hi: now index is :90";
process got a new incoming msg: s:20:"hi: now index is :95";

看到這里是不是，大家已經(jīng)對怎么模擬php為事件驅(qū)動已經(jīng)有了一個概念了？別急，我們繼續(xù)完善。

2. 信號量

信號量的概念，大家應(yīng)該都很熟悉。通過信號量，可以實(shí)現(xiàn)進(jìn)程通信，競爭等。再次就不贅述了，只是簡單的列出php中提供的信號量函數(shù)集

sem_acquire -- acquire a semaphore
sem_get -- get a semaphore id
sem_release -- release a semaphore
sem_remove -- remove a semaphore

具體信息，可以翻閱php手冊。

3. 內(nèi)存共享

php sysvshm提供了一個內(nèi)存共享方案:sysvshm，它是和sysvsem,sysvmsg一個系列的，但在此處，我并沒有使用它，我使用的shmop系列函數(shù)，結(jié)合ticks

function memoryusage(){
 printf("%s: %s<br/>", date("h:i:s",time()), memory_get_usage());
 //var_dump(debug_backtrace());
 //var_dump(__function__);
 //debug_print_backtrace();
}
register_tick_function("memoryusage");
declare(ticks=1){
$shm_key = ftok(__file__, 's');
$shm_id = shmop_open($shm_key, 'c', 0644, 100);
}
printf("size of shared memory is: %s<br/>", shmop_size($shm_id));
$shm_text = shmop_read($shm_id, 0, 100);
eval($shm_text);
if(!empty($share_array)){
 var_dump($share_array);
 $share_array['id'] += 1;
}else{
 $share_array = array('id' => 1);
}
$out_put_str = "$share_array = " . var_export($share_array, true) .";";
$out_put_str = str_pad($out_put_str, 100, " ", str_pad_right);
shmop_write($shm_id, $out_put_str, 0);
?>

運(yùn)行這個例子，不斷刷新，我們可以看到index在遞增。

單單使用這個shmop就能完成一下，php腳本之間共享數(shù)據(jù)的功能：以及，比如緩存，計(jì)數(shù)等等。

更多關(guān)于PHP相關(guān)內(nèi)容感興趣的讀者可查看本站專題：《php curl用法總結(jié)》、《php socket用法總結(jié)》、《PHP網(wǎng)絡(luò)編程技巧總結(jié)》、《php面向?qū)ο蟪绦蛟O(shè)計(jì)入門教程》、《PHP數(shù)組(Array)操作技巧大全》、《php字符串(string)用法總結(jié)》、《php+mysql數(shù)據(jù)庫操作入門教程》及《php常見數(shù)據(jù)庫操作技巧匯總》

希望本文所述對大家PHP程序設(shè)計(jì)有所幫助。

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