CURLOPT_STREAM_DEPENDS - Man Page

#include <curl/curl.h>

CURLcode curl_easy_setopt(CURL *handle, CURLOPT_STREAM_DEPENDS,
                          CURL *dephandle);

Pass a CURL pointer in dephandle to identify the stream within the same connection that this stream is depending upon. This option clears the exclusive bit and is mutually exclusive to the CURLOPT_STREAM_DEPENDS_E(3) option.

The spec says "Including a dependency expresses a preference to allocate resources to the identified stream rather than to the dependent stream."

This option can be set during transfer.

dephandle must not be the same as handle, that makes this function return an error. It must be another easy handle, and it also needs to be a handle of a transfer that is about to be sent over the same HTTP/2 connection for this option to have an actual effect.

NULL

This functionality affects http only

int main(void)
{
  CURL *curl = curl_easy_init();
  CURL *curl2 = curl_easy_init(); /* a second handle */
  if(curl) {
    curl_easy_setopt(curl, CURLOPT_URL, "https://example.com/one");

    /* the second depends on the first */
    curl_easy_setopt(curl2, CURLOPT_URL, "https://example.com/two");
    curl_easy_setopt(curl2, CURLOPT_STREAM_DEPENDS, curl);

    /* then add both to a multi handle and transfer them! */
  }
}

Added in curl 7.46.0

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

CURLMOPT_PIPELINING(3), CURLOPT_HTTP_VERSION(3), CURLOPT_STREAM_DEPENDS_E(3), CURLOPT_STREAM_WEIGHT(3)

curl_easy_setopt(3), CURLOPT_STREAM_DEPENDS_E(3), CURLOPT_STREAM_WEIGHT(3), libcurl-symbols(3).