This example will create a persistent cURL share handle and demonstrate sharing connections between them. If this is executed in a long-lived PHP SAPI, $sh will survive between SAPI requests.

<?php

// Create or retrieve a persistent cURL share handle set to share DNS lookups and connections
$sh = curl_share_init_persistent([CURL_LOCK_DATA_DNS, CURL_LOCK_DATA_CONNECT]);

// Initialize the first cURL handle and assign the share handle to it
$ch1 = curl_init("http://example.com/");
curl_setopt($ch1, CURLOPT_SHARE, $sh);

// Execute the first cURL handle. This may reuse the connection from an earlier SAPI request
curl_exec($ch1);

// Initialize the second cURL handle and assign the share handle to it
$ch2 = curl_init("http://example.com/");
curl_setopt($ch2, CURLOPT_SHARE, $sh);

// Execute the second cURL handle. This will reuse the connection from $ch1
curl_exec($ch2);

?>