76 lines
2.1 KiB
Markdown
76 lines
2.1 KiB
Markdown
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---
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c: Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al.
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SPDX-License-Identifier: curl
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Title: CURLMOPT_MAX_HOST_CONNECTIONS
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Section: 3
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Source: libcurl
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See-also:
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- CURLMOPT_MAXCONNECTS (3)
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- CURLMOPT_MAX_TOTAL_CONNECTIONS (3)
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Protocol:
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- All
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---
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# NAME
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CURLMOPT_MAX_HOST_CONNECTIONS - max number of connections to a single host
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# SYNOPSIS
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~~~c
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#include <curl/curl.h>
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CURLMcode curl_multi_setopt(CURLM *handle, CURLMOPT_MAX_HOST_CONNECTIONS,
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long max);
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~~~
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# DESCRIPTION
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Pass a long to indicate **max**. The set number is used as the maximum amount
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of simultaneously open connections to a single host (a host being the same as
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a hostname + port number pair). For each new session to a host, libcurl might
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open a new connection up to the limit set by CURLMOPT_MAX_HOST_CONNECTIONS(3).
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When the limit is reached, new sessions are kept pending until a connection
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becomes available.
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The default **max** value is 0, unlimited. This set limit is also used for
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proxy connections, and then the proxy is considered to be the host for which
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this limit counts.
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When more transfers are added to the multi handle than what can be performed
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due to the set limit, they are queued up waiting for their chance. When that
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happens, the CURLOPT_TIMEOUT_MS(3) timeout is inclusive of the waiting time,
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meaning that if you set a too narrow timeout in such a case the transfer might
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never even start before it times out.
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Even in the queued up situation, the CURLOPT_CONNECTTIMEOUT_MS(3) timeout is
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however treated as a per-connect timeout.
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Changing this value when there are transfers in progress is possible, and the
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new value is then used the next time checks are performed. Lowering the value
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does however not close down any active transfers, it simply does not allow new
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ones to get made.
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# DEFAULT
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0
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# EXAMPLE
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~~~c
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int main(void)
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{
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CURLM *m = curl_multi_init();
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/* do no more than 2 connections per host */
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curl_multi_setopt(m, CURLMOPT_MAX_HOST_CONNECTIONS, 2L);
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}
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~~~
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# AVAILABILITY
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Added in 7.30.0
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# RETURN VALUE
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Returns CURLM_OK if the option is supported, and CURLM_UNKNOWN_OPTION if not.
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