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| .TH CURLMOPT_MAX_HOST_CONNECTIONS 3 "March 17, 2021" "libcurl 7.78.0" "curl_multi_setopt options" |
| |
| .SH NAME |
| CURLMOPT_MAX_HOST_CONNECTIONS \- set max number of connections to a single host |
| .SH SYNOPSIS |
| #include <curl/curl.h> |
| |
| CURLMcode curl_multi_setopt(CURLM *handle, CURLMOPT_MAX_HOST_CONNECTIONS, long max); |
| .SH DESCRIPTION |
| Pass a long to indicate \fBmax\fP. The set number will be used as the maximum |
| amount of simultaneously open connections to a single host (a host being the |
| same as a host name + port number pair). For each new session to a host, |
| libcurl will open a new connection up to the limit set by |
| \fICURLMOPT_MAX_HOST_CONNECTIONS(3)\fP. When the limit is reached, the |
| sessions will be pending until a connection becomes available. If |
| \fICURLMOPT_PIPELINING(3)\fP is enabled, libcurl will try to pipeline if the |
| host is capable of it. |
| |
| The default \fBmax\fP value is 0, unlimited. However, for backwards |
| compatibility, setting it to 0 when \fICURLMOPT_PIPELINING(3)\fP is 1 will not |
| be treated as unlimited. Instead it will open only 1 connection and try to |
| pipeline on it. |
| |
| This set limit is also used for proxy connections, and then the proxy is |
| considered to be the host for which this limit counts. |
| |
| When more transfers are added to the multi handle than what can be performed |
| due to the set limit, they will be queued up waiting for their chance. When |
| that happens, the \fICURLOPT_TIMEOUT_MS(3)\fP timeout will be counted |
| inclusive of the waiting time, meaning that if you set a too narrow timeout in |
| such a case the transfer might never even start before it times out. |
| |
| Even in the queued up situation, the \fICURLOPT_CONNECTTIMEOUT_MS(3)\fP |
| timeout is however treated as a per-connect timeout. |
| .SH DEFAULT |
| 0 |
| .SH PROTOCOLS |
| HTTP(S) |
| .SH EXAMPLE |
| .nf |
| CURLM *m = curl_multi_init(); |
| /* do no more than 2 connections per host */ |
| curl_multi_setopt(m, CURLMOPT_MAX_HOST_CONNECTIONS, 2L); |
| .fi |
| .SH AVAILABILITY |
| Added in 7.30.0 |
| .SH RETURN VALUE |
| Returns CURLM_OK if the option is supported, and CURLM_UNKNOWN_OPTION if not. |
| .SH "SEE ALSO" |
| .BR CURLMOPT_MAXCONNECTS "(3), " CURLMOPT_MAX_TOTAL_CONNECTIONS "(3), " |
