curl_multi_setopt(3) libcurl Manual curl_multi_setopt(3)NAMEcurl_multi_setopt - set options for a curl multi handle
SYNOPSIS
#include <curl/curl.h>
CURLMcode curl_multi_setopt(CURLM * multi_handle, CURLMoption option,
param);
DESCRIPTIONcurl_multi_setopt() is used to tell a libcurl multi handle how to
behave. By using the appropriate options to curl_multi_setopt(3), you
can change libcurl's behaviour when using that multi handle. All
options are set with the option followed by the parameter param. That
parameter can be a long, a function pointer, an object pointer or a
curl_off_t 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.
OPTIONS
CURLMOPT_SOCKETFUNCTION
Pass a pointer to a function matching the curl_socket_callback
prototype. The curl_multi_socket(3) functions inform the appli‐
cation about updates in the socket (file descriptor) status by
doing none, one or multiple calls to the curl_socket_callback
given in the param argument. They update the status with changes
since the previous time a curl_multi_socket(3) function was
called. If the given callback pointer is NULL, no callback will
be called. Set the callback's userp argument with CURLMOPT_SOCK‐
ETDATA. See curl_multi_socket(3) for more callback details.
CURLMOPT_SOCKETDATA
Pass a pointer to whatever you want passed to the
curl_socket_callback's forth argument, the userp pointer. This
is not used by libcurl but only passed-thru as-is. Set the call‐
back pointer with CURLMOPT_SOCKETFUNCTION.
CURLMOPT_PIPELINING
Pass a long set to 1 to enable or 0 to disable. Enabling pipe‐
lining 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 parallell.
(Added in 7.16.0)
CURLMOPT_TIMERFUNCTION
Pass a pointer to a function matching the curl_multi_timer_call‐
back prototype. 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 (curl_multi_socket(3),
curl_multi_socket_all(3) and curl_multi_perform(3)) - 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
change. See also CURLMOPT_TIMERDATA. This callback can be used
instead of, or in addition to, curl_multi_timeout(3). (Added in
7.16.0)
CURLMOPT_TIMERDATA
Pass a pointer to whatever you want passed to the
curl_multi_timer_callback's third argument, the userp pointer.
This is not used by libcurl but only passed-thru as-is. Set the
callback pointer with CURLMOPT_TIMERFUNCTION. (Added in 7.16.0)
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 han‐
dles.
By setting this option, you can prevent the cache size to grow
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 to increase.
This option is for the multi handle's use only, when using the
easy interface you should instead use the CURLOPT_MAXCONNECTS
option.
(Added in 7.16.3)
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.
AVAILABILITY
This function was added in libcurl 7.15.4.
SEE ALSOcurl_multi_cleanup(3), curl_multi_init(3), curl_multi_socket(3),
curl_multi_info_read(3)libcurl 7.16.0 10 Oct 2006 curl_multi_setopt(3)
