CURLOPT_TCP_KEEPINTVL(3)

👑 NAME 👑

okay so this is the CURLOPT_TCP_KEEPINTVL(3) page, and yes bestie, it lives in the libcurl Library Functions Manual 💖 The actual name energy is: CURLOPT_TCP_KEEPINTVL — TCP keep-alive interval, aka the seconds-between-probes knob 💅

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✨ SYNOPSIS ✨

#include <curl/curl.h>

CURLcode curl_easy_setopt(CURL *handle, CURLOPT_TCP_KEEPINTVL, long interval);

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🦋 DESCRIPTION 🦋

You pass a long, bestie. It sets the interval, in seconds, to wait between sending keepalive probes. So cute, so simple. Not all operating systems support this option, though — that's just the vibe check reality 😭

The maximum value this accepts is 2147483648. Any larger value is capped to this amount. No cap escapes the cap, periodt.

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🎀 DEFAULT 🎀

The default is 60. Slay.

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🌈 PROTOCOLS 🌈

This functionality affects tcp only. That's the whole protocol guest list, iykyk.

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💜 EXAMPLE 💜

Here's the example, verbatim, because we do not mess with code in this house 🫶

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);

    /* set 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);

    /* maximum number of keep-alive probes: 3 */
    curl_easy_setopt(curl, CURLOPT_TCP_KEEPCNT, 3L);

    curl_easy_perform(curl);
  }
}

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⭐ AVAILABILITY ⭐

Added in curl 7.25.0. Vintage-ish but still iconic 👑

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💅 RETURN VALUE 💅

curl_easy_setopt(3) returns a CURLcode indicating success or error.

CURLE_OK (0) means everything was OK, non-zero means an error occurred, see libcurl-errors(3). So like, zero is the good one, bestie 🎀

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🫶 SEE ALSO 🫶

• CURLOPT_TCP_KEEPALIVE(3)
• CURLOPT_TCP_KEEPCNT(3)
• CURLOPT_TCP_KEEPIDLE(3)

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mwah 💋 this page is from libcurl, dated 2026-10-12, and its title is CURLOPT_TCP_KEEPINTVL(3) — that's the cute little footer sign-off, periodt 🌸