Mastering curl_errno(): How to Retrieve and Handle cURL Error Codes in PHP

Function Overview

curl_errno()

is a PHP function that returns the error code of the most recent cURL request. It accepts a cURL handle resource and returns 0 if no error occurred, otherwise a non‑zero error number.

Usage Example

The following example demonstrates initializing a cURL handle, setting options, executing the request, checking for errors with curl_errno(), and closing the handle.

<?php
// Initialize a cURL handle
$ch = curl_init();

// Set cURL options
curl_setopt($ch, CURLOPT_URL, "http://www.example.com");
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);

// Execute the request
$response = curl_exec($ch);

// Check for errors
if (curl_errno($ch)) {
    // Get the error code
    $error_code = curl_errno($ch);
    echo "cURL request failed, error code: " . $error_code;
} else {
    // No error
    echo "cURL request succeeded!";
}

// Close the handle
curl_close($ch);
?>

Explanation of the Example

The script first creates a cURL handle and configures it with the target URL and the CURLOPT_RETURNTRANSFER option so the response is returned as a string. curl_exec() performs the request and stores the result in $response.

After execution, curl_errno($ch) checks whether an error occurred. If an error is detected, the same function retrieves the specific error code, which is then printed. If no error is found, a success message is displayed.

Finally, curl_close($ch) releases the resources associated with the handle.

Common cURL Error Codes

CURLE_COULDNT_CONNECT (7): Unable to connect to the remote host.

CURLE_OPERATION_TIMEDOUT (28): The operation timed out.

CURLE_COULDNT_RESOLVE_HOST (6): Host name could not be resolved.

CURLE_SSL_CONNECT_ERROR (35): SSL connection failed.

CURLE_OK (0): No error.

Conclusion

By using curl_errno(), developers can easily obtain the error code of a cURL request, allowing them to implement precise error handling, improve application stability, and respond appropriately to network issues.