CURLOPT_TCP_NODELAY(3)

CURLOPT_TCP_NODELAY3

The tcp_nodelay option

Usage

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

Overview

Pass a long specifying whether the TCP_NODELAY option is to be set or cleared (1L = set, 0 = clear). The option is set by default. This has no effect after the connection has been established.

Setting this option to 1L disables TCP's Nagle algorithm on connections created using this handle. The purpose of this algorithm is to try to minimize the number of small packets on the network (where "small packets" means TCP segments less than the Maximum Segment Size for the network).

Maximizing the amount of data sent per TCP segment is good because it amortizes the overhead of the send. However, in some cases small segments may need to be sent without delay. This is less efficient than sending larger amounts of data at a time, and can contribute to congestion on the network if overdone.

Default

1

Protocols

All

Examples

int main(void)
{
  CURL *curl = curl_easy_init();
  if(curl) {
    curl_easy_setopt(curl, CURLOPT_URL, "https://example.com");
    /* leave Nagle enabled */
    curl_easy_setopt(curl, CURLOPT_TCP_NODELAY, 0);
    curl_easy_perform(curl);
  }
}

Return value

Returns CURLE_OK

Releases

79 releases since OS X 10.10; the text changed 14 times.

  1. 10.10–10.11.6
  2. 10.12–10.12.1
  3. 10.12.2–10.12.5
  4. 10.12.6–10.14.6
  5. 10.15–11.5
  6. 12.0.1–12.2
  7. 12.3–12.5
  8. 13.0
  9. 13.1
  10. 13.2
  11. 13.3
  12. 13.4
  13. 13.5–14.1
  14. 14.2–14.4
  15. 14.5–26.5

Availability

Always. The default was changed to 1 from 0 in 7.50.2.

From curl 166.0.0.0.1 in macOS 26.5. Parsed by carta from the page's man source.