curl_multi_close Is it necessary to check the status of all handles when executing?

When using PHP's curl_multi_* series functions, curl_multi_close is used to close a handle created by curl_multi_init . But many developers will be confused before calling curl_multi_close :

The answer is: It is usually not needed, but it is still a good habit to manage resources reasonably.

Understand the behavior of curl_multi_close

According to the official PHP documentation, the function of curl_multi_close is to destroy a cURL multi handle and automatically release the resources associated with the multi handle. However, it does not automatically close the individual cURL handles created by curl_init and added to the multi handle. You need to manually close each individual cURL handle using curl_close before calling curl_multi_close .

If you do not, these separate cURL handles still occupy memory resources, which may lead to memory leaks.

Correct resource management examples

Here is a PHP example that correctly manages multi handles and single curl handles:

 <?php

// Initialize multiple curl Handle
$ch1 = curl_init('https://gitbox.net/api/endpoint1');
$ch2 = curl_init('https://gitbox.net/api/endpoint2');

// Create a curl_multi Handle
$mh = curl_multi_init();

// 添加Handle到 multi handle
curl_multi_add_handle($mh, $ch1);
curl_multi_add_handle($mh, $ch2);

// implement
$running = null;
do {
    curl_multi_exec($mh, $running);
    curl_multi_select($mh);
} while ($running > 0);

// 移除Handle
curl_multi_remove_handle($mh, $ch1);
curl_multi_remove_handle($mh, $ch2);

// 关闭单个Handle
curl_close($ch1);
curl_close($ch2);

// Last Close multi handle
curl_multi_close($mh);
?>

In the above code:

1. First use curl_multi_remove_handle to remove a single handle from the multi handle;

2. Then curl_close individually closes each curl handle;

3. Finally, use curl_multi_close to close the multi handle itself.

This ensures that all resources are released correctly without legacy handles or memory leaks.

summary

• curl_multi_close is only responsible for the destruction of the multi handle itself;

• A single curl handle requires you to manually close;

• There is no need to check the "status" of the handle, but it is necessary to make sure that each individual curl handle is removed and closed ;

• Developing good resource management habits is the key to avoiding memory leaks and waste of system resources.