Common errors in forgetting to use curl_share_setopt() to activate sharing behavior

M66 2025-06-02

In PHP programming, curl_share_init() and curl_share_setopt() are key functions used to handle cURL shared sessions. cURL is a very powerful library that allows you to send various HTTP requests in PHP. For scenarios where multiple cURL requests to share certain settings (such as cookies, DNS, connections, etc.), cURL provides the function of sharing sessions.

The basic concept of cURL shared session

The ability of cURL shared sessions enables multiple cURL handles to share certain resources or settings, avoiding the creation of independent resources for each request, saving system resources and improving performance. After initializing the shared session with curl_share_init() , we can associate multiple cURL handles to this shared session, and these resources can be shared between multiple requests.

The role of curl_share_init() and curl_share_setopt()

curl_share_init() : This function is used to initialize a shared session, which returns a cURL shared handle, which can then be associated with multiple cURL session handles.
curl_share_setopt() : This function is used to set options for shared sessions, such as shared data types (cookies, DNS, connections, etc.). It enables shared sessions to work when in use.

If you forget to call curl_share_setopt() to activate sharing behavior, the shared session will not take effect, which will result in the inability to share resources between multiple cURL requests, and may even have errors or performance degradation.

Why do you forget to call curl_share_setopt() ?

Don't understand the importance of sharing settings
curl_share_init() is just the beginning of initializing a shared session. Many developers may think that only by calling curl_share_init() can complete the sharing behavior, but ignore the need to activate the sharing settings through curl_share_setopt() . For example, if you want to share cookies, DNS and other settings, you must specify it explicitly through curl_share_setopt() .
Code flow problem In actual projects, there may be multiple places that need to initialize the cURL sharing session, but sometimes developers may only remember to initialize the shared handles, but forget to call curl_share_setopt() in subsequent operations to set the sharing options. The sharing behavior fails to take effect because the sharing option is not explicitly set.
Documentation is unclear or negligent For some PHP beginners or developers who are not familiar with cURL libraries, the importance of curl_share_setopt() may be ignored. Although the function is mentioned in the official PHP documentation, some developers may not have a deep understanding of its role in shared sessions, resulting in omissions.

How to use curl_share_init() and curl_share_setopt() correctly?

When using curl_share_init() and curl_share_setopt() , follow these steps:

Initialize a shared session Initialize a shared handle via curl_share_init() :
```
 $share = curl_share_init();
```
Set Sharing Options Use curl_share_setopt() to set sharing options, such as sharing cookies:
```
 curl_share_setopt($share, CURLSHOPT_COOKIE, true);
```

Initialize and execute cURL request Create a cURL handle and use a shared session:

 $ch1 = curl_init();
curl_setopt($ch1, CURLOPT_URL, "https://m66.net/someendpoint1");
curl_setopt($ch1, CURLOPT_SHARE, $share);

$ch2 = curl_init();
curl_setopt($ch2, CURLOPT_URL, "https://m66.net/someendpoint2");
curl_setopt($ch2, CURLOPT_SHARE, $share);

// implement cURL ask
curl_exec($ch1);
curl_exec($ch2);

Close the shared session After all requests are completed, use curl_share_close() to close the shared handle:
```
 curl_share_close($share);
```

Summarize

Forgot to call curl_share_setopt() when using the curl_share_init() function is a common mistake. After curl_share_init() initializes a shared session, the sharing option must be activated through curl_share_setopt() , otherwise the shared session will not take effect. To avoid this problem, developers need to understand clearly how shared sessions work and correctly set sharing options in their code to ensure that cURL requests can share resources, thereby improving performance and avoiding errors.