1curl_multi_setopt(3) libcurl Manual curl_multi_setopt(3)
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6 curl_multi_setopt - set options for a curl multi handle
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9 #include <curl/curl.h>
10 CURLMcode curl_multi_setopt(CURLM * multi_handle, CURLMoption option,
12 param);
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15 curl_multi_setopt() is used to tell a libcurl multi handle how to
16 behave. By using the appropriate options to curl_multi_setopt(3), you
17 can change libcurl's behaviour when using that multi handle. All
18 options are set with the option followed by the parameter param. That
19 parameter can be a long, a function pointer, an object pointer or a
20 curl_off_t type, depending on what the specific option expects. Read
21 this manual carefully as bad input values may cause libcurl to behave
22 badly! You can only set one option in each function call.
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26 CURLMOPT_SOCKETFUNCTION
27 Pass a pointer to a function matching the curl_socket_callback
28 prototype. The curl_multi_socket_action(3) function informs the
29 application about updates in the socket (file descriptor) status
30 by doing none, one, or multiple calls to the curl_socket_call‐
31 back given in the param argument. They update the status with
32 changes since the previous time a curl_multi_socket(3) function
33 was called. If the given callback pointer is NULL, no callback
34 will be called. Set the callback's userp argument with CURL‐
35 MOPT_SOCKETDATA. See curl_multi_socket(3) for more callback
36 details.
37 CURLMOPT_SOCKETDATA
39 Pass a pointer to whatever you want passed to the
40 curl_socket_callback's forth argument, the userp pointer. This
41 is not used by libcurl but only passed-thru as-is. Set the call‐
42 back pointer with CURLMOPT_SOCKETFUNCTION.
43 CURLMOPT_PIPELINING
45 Pass a long set to 1 to enable or 0 to disable. Enabling pipe‐
46 lining on a multi handle will make it attempt to perform HTTP
47 Pipelining as far as possible for transfers using this handle.
48 This means that if you add a second request that can use an
49 already existing connection, the second request will be "piped"
50 on the same connection rather than being executed in parallel.
51 (Added in 7.16.0)
52 CURLMOPT_TIMERFUNCTION
54 Pass a pointer to a function matching the curl_multi_timer_call‐
55 back prototype. This function will then be called when the
56 timeout value changes. The timeout value is at what latest time
57 the application should call one of the "performing" functions of
58 the multi interface (curl_multi_socket_action(3) and
59 curl_multi_perform(3)) - to allow libcurl to keep timeouts and
60 retries etc to work. A timeout value of -1 means that there is
61 no timeout at all, and 0 means that the timeout is already
62 reached. Libcurl attempts to limit calling this only when the
63 fixed future timeout time actually changes. See also CURL‐
64 MOPT_TIMERDATA. This callback can be used instead of, or in
65 addition to, curl_multi_timeout(3). (Added in 7.16.0)
66 CURLMOPT_TIMERDATA
68 Pass a pointer to whatever you want passed to the
69 curl_multi_timer_callback's third argument, the userp pointer.
70 This is not used by libcurl but only passed-thru as-is. Set the
71 callback pointer with CURLMOPT_TIMERFUNCTION. (Added in 7.16.0)
72 CURLMOPT_MAXCONNECTS
74 Pass a long. The set number will be used as the maximum amount
75 of simultaneously open connections that libcurl may cache.
76 Default is 10, and libcurl will enlarge the size for each added
77 easy handle to make it fit 4 times the number of added easy han‐
78 dles.
79 By setting this option, you can prevent the cache size from
81 growing beyond the limit set by you.
82 When the cache is full, curl closes the oldest one in the cache
84 to prevent the number of open connections from increasing.
85 This option is for the multi handle's use only, when using the
87 easy interface you should instead use the CURLOPT_MAXCONNECTS
88 option.
89 (Added in 7.16.3)
91
93 The standard CURLMcode for multi interface error codes. Note that it
94 returns a CURLM_UNKNOWN_OPTION if you try setting an option that this
95 version of libcurl doesn't know of.
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98 This function was added in libcurl 7.15.4.
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101 curl_multi_cleanup(3), curl_multi_init(3), curl_multi_socket(3),
102 curl_multi_info_read(3)
103libcurl 7.16.0 10 Oct 2006 curl_multi_setopt(3)