CURLOPT_TCP_KEEPALIVE(3) Library Functions Manual CURLOPT_TCP_KEEPALIVE(3)

CURLOPT_TCP_KEEPALIVE - TCP keep-alive probing

#include <curl/curl.h>
CURLcode curl_easy_setopt(CURL *handle, CURLOPT_TCP_KEEPALIVE, long probe);

Pass a long. If set to 1, TCP keepalive probes are used. The delay and frequency of these probes can be controlled by the CURLOPT_TCP_KEEPIDLE(3) and CURLOPT_TCP_KEEPINTVL(3) options, provided the operating system supports them. Set to 0 (default behavior) to disable keepalive probes

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int main(void)
{
  CURL *curl = curl_easy_init();
  if(curl) {
    curl_easy_setopt(curl, CURLOPT_URL, "https://example.com");
    /* enable TCP keep-alive for this transfer */
    curl_easy_setopt(curl, CURLOPT_TCP_KEEPALIVE, 1L);
    /* keep-alive idle time to 120 seconds */
    curl_easy_setopt(curl, CURLOPT_TCP_KEEPIDLE, 120L);
    /* interval time between keep-alive probes: 60 seconds */
    curl_easy_setopt(curl, CURLOPT_TCP_KEEPINTVL, 60L);
    curl_easy_perform(curl);
  }
}

Added in 7.25.0

Returns CURLE_OK if the option is supported, and CURLE_UNKNOWN_OPTION if not.

CURLOPT_LOW_SPEED_LIMIT(3), CURLOPT_MAX_RECV_SPEED_LARGE(3), CURLOPT_TCP_KEEPIDLE(3), CURLOPT_TCP_KEEPINTVL(3)

2024-05-22 libcurl