在进行并发操作时,会导致共享数据的完整性的问题,要加入锁,在任意时刻只有一个线程访问该对象
在PHP中定义专门用于线程同步控制的mutex的函数, pthreads v3 中已经将 Mutex 类移除。
简单的计数器程序,有加锁和没有加锁的情况,pthreads v3使用synchronized同步处理
<?php class CounterThread extends Thread { public $counter = 0; public $handle; public $mutex; public function __construct($handle,$mutex = null){ $this->mutex = $mutex; } public function run() { //加锁 if($this->mutex){ $locked=Mutex::lock($this->mutex); } $this->handle = fopen("/tmp/counter.txt", "w+"); $this->counter = intval(fgets($this->handle)); $this->counter++; rewind($this->handle); fwrite($this->handle, $this->counter." "); printf("Thread #%lu says: %s ", $this->getThreadId(),$this->counter); $this->close(); if($this->mutex){ //释放锁 Mutex::unlock($this->mutex); } } public function close() { print_r(fclose( $this->handle));echo PHP_EOL; } } $handle=fopen("/tmp/counter.txt", "w+"); //没有互斥锁 for ($i=0;$i<10;$i++){ $threads[$i] = new CounterThread($handle); $threads[$i]->start(); sleep(1); } //创建一个互斥锁 //参数设置true,表示创建互斥量之后,立即加锁, $mutex = Mutex::create(); for ($i=0;$i<10;$i++){ $threads[$i] = new CounterThread($handle,$mutex); $threads[$i]->start(); sleep(1); } //销毁互斥量 Mutex::destroy($mutex); /* Mutex::unlock($mutex); for ($i=0;$i<50;$i++){ $threads[$i]->join(); } Mutex::destroy($mutex); */ ?>