Performs any connection upkeep checks

# curl_upkeep

(PHP 8 >= 8.2.0)

curl_upkeep — Performs any connection upkeep checks

### 说明

function curl_upkeep(CurlHandle `$handle`): bool

Available if built against libcurl >= 7.62.0.

Some protocols have "connection upkeep" mechanisms. These mechanisms usually send some traffic on existing connections in order to keep them alive; this can prevent connections from being closed due to overzealous firewalls, for example.

Connection upkeep is currently available only for HTTP/2 connections. A small amount of traffic is usually sent to keep a connection alive. HTTP/2 maintains its connection by sending a HTTP/2 PING frame.

### 参数

`handle`
  由 curl_init() 返回的 cURL 句柄。

### 返回值

成功时返回 `true`， 或者在失败时返回 `false`。

### 示例

示例 #1 curl_upkeep() example

    <?php
    $url = "https://example.com";

    $ch = curl_init();
    curl_setopt($ch, CURLOPT_URL, $url);
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
    curl_setopt($ch, CURLOPT_HTTP_VERSION,CURL_HTTP_VERSION_2_0);
    curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);
    curl_setopt($ch, CURLOPT_UPKEEP_INTERVAL_MS, 200);
    if (curl_exec($ch)) {
        usleep(300);
        var_dump(curl_upkeep($ch));
    }
    ?>

### 参见

- curl_init() - 初始化 cURL 会话

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