curl/docs/libcurl/opts/CURLOPT_STREAM_DEPENDS_E.md

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---
c: Copyright (C) Daniel Stenberg, <daniel.se>, et al.
SPDX-License-Identifier: curl
Title: CURLOPT_STREAM_DEPENDS_E
Section: 3
Source: libcurl
See-also:
- CURLMOPT_PIPELINING (3)
- CURLOPT_HTTP_VERSION (3)
- CURLOPT_STREAM_DEPENDS (3)
- CURLOPT_STREAM_WEIGHT (3)
---
# NAME
CURLOPT_STREAM_DEPENDS_E - stream this transfer depends on exclusively
# SYNOPSIS
~~~c
#include <curl/curl.h>
CURLcode curl_easy_setopt(CURL *handle, CURLOPT_STREAM_DEPENDS_E,
CURL *dephandle);
~~~
# DESCRIPTION
Pass a CURL pointer in *dephandle* to identify the stream within the same
connection that this stream is depending upon exclusively. That means it
depends on it and sets the Exclusive bit.
The spec says "Including a dependency expresses a preference to allocate
resources to the identified stream rather than to the dependent stream."
Setting a dependency with the exclusive flag for a reprioritized stream causes
all the dependencies of the new parent stream to become dependent on the
reprioritized 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.
# DEFAULT
NULL
# PROTOCOLS
HTTP/2
# EXAMPLE
~~~c
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_E, curl);
/* then add both to a multi handle and transfer them! */
}
}
~~~
# AVAILABILITY
Added in 7.46.0
# RETURN VALUE
Returns CURLE_OK if the option is supported, and CURLE_UNKNOWN_OPTION if not.