docs/libcurl/curl_multi_setopt.3 - third_party/curl - Git at Google

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 .\" *                                  _   _ ____  _
 .\" *  Project                     ___| | | |  _ \| |
 .\" *                             / __| | | | |_) | |
 .\" *                            | (__| |_| |  _ <| |___
 .\" *                             \___|\___/|_| \_\_____|
 .\" *
 .\" * Copyright (C) 1998 - 2011, Daniel Stenberg, <daniel@haxx.se>, et al.
 .\" *
 .\" * This software is licensed as described in the file COPYING, which
 .\" * you should have received as part of this distribution. The terms
 .\" * are also available at http://curl.haxx.se/docs/copyright.html.
 .\" *
 .\" * You may opt to use, copy, modify, merge, publish, distribute and/or sell
 .\" * copies of the Software, and permit persons to whom the Software is
 .\" * furnished to do so, under the terms of the COPYING file.
 .\" *
 .\" * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
 .\" * KIND, either express or implied.
 .\" *
 .\" **************************************************************************
 .TH curl_multi_setopt 3 "10 Oct 2006" "libcurl 7.16.0" "libcurl Manual"
 .SH NAME
 curl_multi_setopt \- set options for a curl multi handle
 .SH SYNOPSIS
 #include <curl/curl.h>

 CURLMcode curl_multi_setopt(CURLM * multi_handle, CURLMoption option, param);
 .SH DESCRIPTION
 curl_multi_setopt() is used to tell a libcurl multi handle how to behave. By
 using the appropriate options to \fIcurl_multi_setopt(3)\fP, you can change
 libcurl's behaviour when using that multi handle.  All options are set with
 the \fIoption\fP followed by the parameter \fIparam\fP. That parameter can be
 a \fBlong\fP, a \fBfunction pointer\fP, an \fBobject pointer\fP or a
 \fBcurl_off_t\fP type, depending on what the specific option expects. Read
 this manual carefully as bad input values may cause libcurl to behave badly!
 You can only set one option in each function call.

 .SH OPTIONS
 .IP CURLMOPT_SOCKETFUNCTION
 Pass a pointer to a function matching the \fBcurl_socket_callback\fP
 prototype. The \fIcurl_multi_socket_action(3)\fP function informs the
 application about updates in the socket (file descriptor) status by doing
 none, one, or multiple calls to the curl_socket_callback given in the
 \fBparam\fP argument. They update the status with changes since the previous
 time a \fIcurl_multi_socket(3)\fP function was called. If the given callback
 pointer is NULL, no callback will be called. Set the callback's \fBuserp\fP
 argument with \fICURLMOPT_SOCKETDATA\fP.  See \fIcurl_multi_socket(3)\fP for
 more callback details.
 .IP CURLMOPT_SOCKETDATA
 Pass a pointer to whatever you want passed to the \fBcurl_socket_callback\fP's
 fourth argument, the userp pointer. This is not used by libcurl but only
 passed-thru as-is. Set the callback pointer with
 \fICURLMOPT_SOCKETFUNCTION\fP.
 .IP CURLMOPT_PIPELINING
 Pass a long set to 1 to enable or 0 to disable. Enabling pipelining on a multi
 handle will make it attempt to perform HTTP Pipelining as far as possible for
 transfers using this handle. This means that if you add a second request that
 can use an already existing connection, the second request will be \&"piped"
 on the same connection rather than being executed in parallel. (Added in
 7.16.0)
 .IP CURLMOPT_TIMERFUNCTION
 Pass a pointer to a function matching the \fBcurl_multi_timer_callback\fP
 prototype: int curl_multi_timer_callback(CURLM *multi /* multi handle */,
 long timeout_ms /* timeout in milliseconds */, void *userp /* TIMERDATA */).
 This function will then be called when the timeout value
 changes. The timeout value is at what latest time the application should call
 one of the \&"performing" functions of the multi interface
 (\fIcurl_multi_socket_action(3)\fP and \fIcurl_multi_perform(3)\fP) - to allow
 libcurl to keep timeouts and retries etc to work. A timeout value of -1 means
 that there is no timeout at all, and 0 means that the timeout is already
 reached. Libcurl attempts to limit calling this only when the fixed future
 timeout time actually changes. See also \fICURLMOPT_TIMERDATA\fP. The callback
 should return 0 on success, and -1 on error. This
 callback can be used instead of, or in addition to,
 \fIcurl_multi_timeout(3)\fP. (Added in 7.16.0)
 .IP CURLMOPT_TIMERDATA
 Pass a pointer to whatever you want passed to the
 \fBcurl_multi_timer_callback\fP's third argument, the userp pointer.  This is
 not used by libcurl but only passed-thru as-is. Set the callback pointer with
 \fICURLMOPT_TIMERFUNCTION\fP. (Added in 7.16.0)
 .IP CURLMOPT_MAXCONNECTS
 Pass a long. The set number will be used as the maximum amount of
 simultaneously open connections that libcurl may cache. Default is 10, and
 libcurl will enlarge the size for each added easy handle to make it fit 4
 times the number of added easy handles.

 By setting this option, you can prevent the cache size from growing beyond the
 limit set by you.

 When the cache is full, curl closes the oldest one in the cache to prevent the
 number of open connections from increasing.

 This option is for the multi handle's use only, when using the easy interface
 you should instead use the \fICURLOPT_MAXCONNECTS\fP option.

 (Added in 7.16.3)
 .IP CURLMOPT_MAX_HOST_CONNECTIONS
 Pass a long. The set number will be used as the maximum amount of
 simultaneously open connections to a single host. For each new session to
 a host, libcurl will open a new connection up to the limit set by
 CURLMOPT_MAX_HOST_CONNECTIONS. When the limit is reached, the sessions will
 be pending until there are available connections. If CURLMOPT_PIPELINING is
 1, libcurl will try to pipeline if the host is capable of it.

 The default value is 0, which means that there is no limit.
 However, for backwards compatibility, setting it to 0 when CURLMOPT_PIPELINING
 is 1 will not be treated as unlimited. Instead it will open only 1 connection
 and try to pipeline on it.

 (Added in 7.30.0)
 .IP CURLMOPT_MAX_PIPELINE_LENGTH
 Pass a long. The set number will be used as the maximum amount of requests
 in a pipelined connection. When this limit is reached, libcurl will use another
 connection to the same host (see CURLMOPT_MAX_HOST_CONNECTIONS), or queue the
 requests until one of the pipelines to the host is ready to accept a request.
 Thus, the total number of requests in-flight is CURLMOPT_MAX_HOST_CONNECTIONS *
 CURLMOPT_MAX_PIPELINE_LENGTH.
 The default value is 5.

 (Added in 7.30.0)
 .IP CURLMOPT_CONTENT_LENGTH_PENALTY_SIZE
 Pass a long. If a pipelined connection is currently processing a request
 with a Content-Length larger than CURLMOPT_CONTENT_LENGTH_PENALTY_SIZE, that
 connection will not be considered for additional requests, even if it is
 shorter than CURLMOPT_MAX_PIPELINE_LENGTH.
 The default value is 0, which means that the penalization is inactive.

 (Added in 7.30.0)
 .IP CURLMOPT_CHUNK_LENGTH_PENALTY_SIZE
 Pass a long. If a pipelined connection is currently processing a
 chunked (Transfer-encoding: chunked) request with a current chunk length
 larger than CURLMOPT_CHUNK_LENGTH_PENALTY_SIZE, that connection will not be
 considered for additional requests, even if it is shorter than
 CURLMOPT_MAX_PIPELINE_LENGTH.
 The default value is 0, which means that the penalization is inactive.

 (Added in 7.30.0)
 .IP CURLMOPT_PIPELINING_SITE_BL
 Pass an array of char *, ending with NULL. This is a list of sites that are
 blacklisted from pipelining, i.e sites that are known to not support HTTP
 pipelining. The array is copied by libcurl.

 The default value is NULL, which means that there is no blacklist.

 Pass a NULL pointer to clear the blacklist.

 Example:

 .nf
   site_blacklist[] =
   {
     "www.haxx.se",
     "www.example.com:1234",
     NULL
   };

   curl_multi_setopt(m, CURLMOPT_PIPELINE_SITE_BL, site_blacklist);
 .fi

 (Added in 7.30.0)
 .IP CURLMOPT_PIPELINING_SERVER_BL
 Pass an array of char *, ending with NULL. This is a list of server types
 prefixes (in the Server: HTTP header) that are blacklisted from pipelining,
 i.e server types that are known to not support HTTP pipelining. The array is
 copied by libcurl.

 Note that the comparison matches if the Server: header begins with the string
 in the blacklist, i.e "Server: Ninja 1.2.3" and "Server: Ninja 1.4.0" can
 both be blacklisted by having "Ninja" in the backlist.

 The default value is NULL, which means that there is no blacklist.

 Pass a NULL pointer to clear the blacklist.

 Example:

 .nf
   server_blacklist[] =
   {
     "Microsoft-IIS/6.0",
     "nginx/0.8.54",
     NULL
   };

   curl_multi_setopt(m, CURLMOPT_PIPELINE_SERVER_BL, server_blacklist);
 .fi

 (Added in 7.30.0)
 .IP CURLMOPT_MAX_TOTAL_CONNECTIONS
 Pass a long. The set number will be used as the maximum amount of
 simultaneously open connections in total. For each new session, libcurl
 will open a new connection up to the limit set by
 CURLMOPT_MAX_TOTAL_CONNECTIONS. When the limit is reached, the sessions will
 be pending until there are available connections. If CURLMOPT_PIPELINING is
 1, libcurl will try to pipeline if the host is capable of it.

 The default value is 0, which means that there is no limit.
 However, for backwards compatibility, setting it to 0 when CURLMOPT_PIPELINING
 is 1 will not be treated as unlimited. Instead it will open only 1 connection
 and try to pipeline on it.

 (Added in 7.30.0)
 .SH RETURNS
 The standard CURLMcode for multi interface error codes. Note that it returns a
 CURLM_UNKNOWN_OPTION if you try setting an option that this version of libcurl
 doesn't know of.
 .SH AVAILABILITY
 This function was added in libcurl 7.15.4.
 .SH "SEE ALSO"
 .BR curl_multi_cleanup "(3), " curl_multi_init "(3), "
 .BR curl_multi_socket "(3), " curl_multi_info_read "(3)"
	.\" **************************************************************************
	.\" * _ _ ____ _
	.\" * Project ___\| \| \| \| _ \\| \|
	.\" * / __\| \| \| \| \|_) \| \|
	.\" * \| (__\| \|_\| \| _ <\| \|___
	.\" * \___\|\___/\|_\| \_\_____\|
	.\" *
	.\" * Copyright (C) 1998 - 2011, Daniel Stenberg, <daniel@haxx.se>, et al.
	.\" *
	.\" * This software is licensed as described in the file COPYING, which
	.\" * you should have received as part of this distribution. The terms
	.\" * are also available at http://curl.haxx.se/docs/copyright.html.
	.\" *
	.\" * You may opt to use, copy, modify, merge, publish, distribute and/or sell
	.\" * copies of the Software, and permit persons to whom the Software is
	.\" * furnished to do so, under the terms of the COPYING file.
	.\" *
	.\" * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
	.\" * KIND, either express or implied.
	.\" *
	.\" **************************************************************************
	.TH curl_multi_setopt 3 "10 Oct 2006" "libcurl 7.16.0" "libcurl Manual"
	.SH NAME
	curl_multi_setopt \- set options for a curl multi handle
	.SH SYNOPSIS
	#include <curl/curl.h>

	CURLMcode curl_multi_setopt(CURLM * multi_handle, CURLMoption option, param);
	.SH DESCRIPTION
	curl_multi_setopt() is used to tell a libcurl multi handle how to behave. By
	using the appropriate options to \fIcurl_multi_setopt(3)\fP, you can change
	libcurl's behaviour when using that multi handle. All options are set with
	the \fIoption\fP followed by the parameter \fIparam\fP. That parameter can be
	a \fBlong\fP, a \fBfunction pointer\fP, an \fBobject pointer\fP or a
	\fBcurl_off_t\fP type, depending on what the specific option expects. Read
	this manual carefully as bad input values may cause libcurl to behave badly!
	You can only set one option in each function call.

	.SH OPTIONS
	.IP CURLMOPT_SOCKETFUNCTION
	Pass a pointer to a function matching the \fBcurl_socket_callback\fP
	prototype. The \fIcurl_multi_socket_action(3)\fP function informs the
	application about updates in the socket (file descriptor) status by doing
	none, one, or multiple calls to the curl_socket_callback given in the
	\fBparam\fP argument. They update the status with changes since the previous
	time a \fIcurl_multi_socket(3)\fP function was called. If the given callback
	pointer is NULL, no callback will be called. Set the callback's \fBuserp\fP
	argument with \fICURLMOPT_SOCKETDATA\fP. See \fIcurl_multi_socket(3)\fP for
	more callback details.
	.IP CURLMOPT_SOCKETDATA
	Pass a pointer to whatever you want passed to the \fBcurl_socket_callback\fP's
	fourth argument, the userp pointer. This is not used by libcurl but only
	passed-thru as-is. Set the callback pointer with
	\fICURLMOPT_SOCKETFUNCTION\fP.
	.IP CURLMOPT_PIPELINING
	Pass a long set to 1 to enable or 0 to disable. Enabling pipelining on a multi
	handle will make it attempt to perform HTTP Pipelining as far as possible for
	transfers using this handle. This means that if you add a second request that
	can use an already existing connection, the second request will be \&"piped"
	on the same connection rather than being executed in parallel. (Added in
	7.16.0)
	.IP CURLMOPT_TIMERFUNCTION
	Pass a pointer to a function matching the \fBcurl_multi_timer_callback\fP
	prototype: int curl_multi_timer_callback(CURLM multi / multi handle */,
	long timeout_ms /* timeout in milliseconds /, void userp /* TIMERDATA */).
	This function will then be called when the timeout value
	changes. The timeout value is at what latest time the application should call
	one of the \&"performing" functions of the multi interface
	(\fIcurl_multi_socket_action(3)\fP and \fIcurl_multi_perform(3)\fP) - to allow
	libcurl to keep timeouts and retries etc to work. A timeout value of -1 means
	that there is no timeout at all, and 0 means that the timeout is already
	reached. Libcurl attempts to limit calling this only when the fixed future
	timeout time actually changes. See also \fICURLMOPT_TIMERDATA\fP. The callback
	should return 0 on success, and -1 on error. This
	callback can be used instead of, or in addition to,
	\fIcurl_multi_timeout(3)\fP. (Added in 7.16.0)
	.IP CURLMOPT_TIMERDATA
	Pass a pointer to whatever you want passed to the
	\fBcurl_multi_timer_callback\fP's third argument, the userp pointer. This is
	not used by libcurl but only passed-thru as-is. Set the callback pointer with
	\fICURLMOPT_TIMERFUNCTION\fP. (Added in 7.16.0)
	.IP CURLMOPT_MAXCONNECTS
	Pass a long. The set number will be used as the maximum amount of
	simultaneously open connections that libcurl may cache. Default is 10, and
	libcurl will enlarge the size for each added easy handle to make it fit 4
	times the number of added easy handles.

	By setting this option, you can prevent the cache size from growing beyond the
	limit set by you.

	When the cache is full, curl closes the oldest one in the cache to prevent the
	number of open connections from increasing.

	This option is for the multi handle's use only, when using the easy interface
	you should instead use the \fICURLOPT_MAXCONNECTS\fP option.

	(Added in 7.16.3)
	.IP CURLMOPT_MAX_HOST_CONNECTIONS
	Pass a long. The set number will be used as the maximum amount of
	simultaneously open connections to a single host. For each new session to
	a host, libcurl will open a new connection up to the limit set by
	CURLMOPT_MAX_HOST_CONNECTIONS. When the limit is reached, the sessions will
	be pending until there are available connections. If CURLMOPT_PIPELINING is
	1, libcurl will try to pipeline if the host is capable of it.

	The default value is 0, which means that there is no limit.
	However, for backwards compatibility, setting it to 0 when CURLMOPT_PIPELINING
	is 1 will not be treated as unlimited. Instead it will open only 1 connection
	and try to pipeline on it.

	(Added in 7.30.0)
	.IP CURLMOPT_MAX_PIPELINE_LENGTH
	Pass a long. The set number will be used as the maximum amount of requests
	in a pipelined connection. When this limit is reached, libcurl will use another
	connection to the same host (see CURLMOPT_MAX_HOST_CONNECTIONS), or queue the
	requests until one of the pipelines to the host is ready to accept a request.
	Thus, the total number of requests in-flight is CURLMOPT_MAX_HOST_CONNECTIONS *
	CURLMOPT_MAX_PIPELINE_LENGTH.
	The default value is 5.

	(Added in 7.30.0)
	.IP CURLMOPT_CONTENT_LENGTH_PENALTY_SIZE
	Pass a long. If a pipelined connection is currently processing a request
	with a Content-Length larger than CURLMOPT_CONTENT_LENGTH_PENALTY_SIZE, that
	connection will not be considered for additional requests, even if it is
	shorter than CURLMOPT_MAX_PIPELINE_LENGTH.
	The default value is 0, which means that the penalization is inactive.

	(Added in 7.30.0)
	.IP CURLMOPT_CHUNK_LENGTH_PENALTY_SIZE
	Pass a long. If a pipelined connection is currently processing a
	chunked (Transfer-encoding: chunked) request with a current chunk length
	larger than CURLMOPT_CHUNK_LENGTH_PENALTY_SIZE, that connection will not be
	considered for additional requests, even if it is shorter than
	CURLMOPT_MAX_PIPELINE_LENGTH.
	The default value is 0, which means that the penalization is inactive.

	(Added in 7.30.0)
	.IP CURLMOPT_PIPELINING_SITE_BL
	Pass an array of char *, ending with NULL. This is a list of sites that are
	blacklisted from pipelining, i.e sites that are known to not support HTTP
	pipelining. The array is copied by libcurl.

	The default value is NULL, which means that there is no blacklist.

	Pass a NULL pointer to clear the blacklist.

	Example:

	.nf
	site_blacklist[] =
	{
	"www.haxx.se",
	"www.example.com:1234",
	NULL
	};

	curl_multi_setopt(m, CURLMOPT_PIPELINE_SITE_BL, site_blacklist);
	.fi

	(Added in 7.30.0)
	.IP CURLMOPT_PIPELINING_SERVER_BL
	Pass an array of char *, ending with NULL. This is a list of server types
	prefixes (in the Server: HTTP header) that are blacklisted from pipelining,
	i.e server types that are known to not support HTTP pipelining. The array is
	copied by libcurl.

	Note that the comparison matches if the Server: header begins with the string
	in the blacklist, i.e "Server: Ninja 1.2.3" and "Server: Ninja 1.4.0" can
	both be blacklisted by having "Ninja" in the backlist.

	The default value is NULL, which means that there is no blacklist.

	Pass a NULL pointer to clear the blacklist.

	Example:

	.nf
	server_blacklist[] =
	{
	"Microsoft-IIS/6.0",
	"nginx/0.8.54",
	NULL
	};

	curl_multi_setopt(m, CURLMOPT_PIPELINE_SERVER_BL, server_blacklist);
	.fi

	(Added in 7.30.0)
	.IP CURLMOPT_MAX_TOTAL_CONNECTIONS
	Pass a long. The set number will be used as the maximum amount of
	simultaneously open connections in total. For each new session, libcurl
	will open a new connection up to the limit set by
	CURLMOPT_MAX_TOTAL_CONNECTIONS. When the limit is reached, the sessions will
	be pending until there are available connections. If CURLMOPT_PIPELINING is
	1, libcurl will try to pipeline if the host is capable of it.

	The default value is 0, which means that there is no limit.
	However, for backwards compatibility, setting it to 0 when CURLMOPT_PIPELINING
	is 1 will not be treated as unlimited. Instead it will open only 1 connection
	and try to pipeline on it.

	(Added in 7.30.0)
	.SH RETURNS
	The standard CURLMcode for multi interface error codes. Note that it returns a
	CURLM_UNKNOWN_OPTION if you try setting an option that this version of libcurl
	doesn't know of.
	.SH AVAILABILITY
	This function was added in libcurl 7.15.4.
	.SH "SEE ALSO"
	.BR curl_multi_cleanup "(3), " curl_multi_init "(3), "
	.BR curl_multi_socket "(3), " curl_multi_info_read "(3)"