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等待超时 - Windows(Waiting with timeout - Windows)

 我的程序，在C ++中，有一个线程将数据插入缓冲区，另一个读取此数据的线程。 当没有更多数据要读取时，我要等到另一个线程插入新数据。 我主要在linux上工作，但我不知道如何在Windows中做到这一点。 我发现的最相似的东西是“WaitForSingleObject”函数，但它并不完全是我需要的，因为我不想哭，直到插入数据的线程死了。  
 有人可以指导我到一个我可以阅读更多的地方吗？ 谢谢！ 

My program , in C++, has a thread that insets data to a buffer, and another thead that reads this data. when there is no more data to read, I wan to wait till the other thread inserts new data. I mostly work on linux, but I dont know how to do it in Windows. the most similar thing that I've found is the "WaitForSingleObject" function, but it's not exactly what I need since I dont want to wail till the thread that inserts data is dead. 
can someone please direct me to a place I can read about this more? thanks!

原文：https://stackoverflow.com/questions/12934280

更新时间：2023-08-18 12:08

最满意答案

 您可以使用PDOStatement的rowCount()方法来获取返回的行数：  
$stmt = $dbh->prepare("SELECT * FROM customers where customer_email = ? LIMIT 1");
if ($stmt->execute(array($_POST['customer_email']))) {
    if($stmt->rowCount() > 0) {
       //fetch stuff...
    }
}  
 
 或者，如果rowCount()证明不可靠，那么可以这样做：  
$all = $stmt->fetchAll();
if(count($all)) {
   //loop through the set...
}

You can use the rowCount() method of PDOStatement to get the number of rows returned: 
$stmt = $dbh->prepare("SELECT * FROM customers where customer_email = ? LIMIT 1");
if ($stmt->execute(array($_POST['customer_email']))) {
    if($stmt->rowCount() > 0) {
       //fetch stuff...
    }
}  
 
Or, if rowCount() proves to be unreliable, you can do this: 
$all = $stmt->fetchAll();
if(count($all)) {
   //loop through the set...
}

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