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/***************************************************************************
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* Project ___| | | | _ \| |
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* | (__| |_| | _ <| |___
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* \___|\___/|_| \_\_____|
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* Copyright (C) 1998 - 2007, Daniel Stenberg, <daniel@haxx.se>, et al.
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* This software is licensed as described in the file COPYING, which
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* you should have received as part of this distribution. The terms
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* are also available at http://curl.haxx.se/docs/copyright.html.
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* You may opt to use, copy, modify, merge, publish, distribute and/or sell
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* copies of the Software, and permit persons to whom the Software is
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* furnished to do so, under the terms of the COPYING file.
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* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
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* KIND, either express or implied.
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* $Id: multi.h,v 1.44 2007-05-30 20:04:44 bagder Exp $
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***************************************************************************/
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This is an "external" header file. Don't give away any internals here!
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o Enable a "pull" interface. The application that uses libcurl decides where
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and when to ask libcurl to get/send data.
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o Enable multiple simultaneous transfers in the same thread without making it
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complicated for the application.
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o Enable the application to select() on its own file descriptors and curl's
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file descriptors simultaneous easily.
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* This header file should not really need to include "curl.h" since curl.h
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* itself includes this file and we expect user applications to do #include
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* <curl/curl.h> without the need for especially including multi.h.
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* For some reason we added this include here at one point, and rather than to
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* break existing (wrongly written) libcurl applications, we leave it as-is
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* but with this warning attached.
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CURLM_CALL_MULTI_PERFORM = -1, /* please call curl_multi_perform() or
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curl_multi_socket*() soon */
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CURLM_BAD_HANDLE, /* the passed-in handle is not a valid CURLM handle */
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CURLM_BAD_EASY_HANDLE, /* an easy handle was not good/valid */
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CURLM_OUT_OF_MEMORY, /* if you ever get this, you're in deep sh*t */
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CURLM_INTERNAL_ERROR, /* this is a libcurl bug */
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CURLM_BAD_SOCKET, /* the passed in socket argument did not match */
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CURLM_UNKNOWN_OPTION, /* curl_multi_setopt() with unsupported option */
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/* just to make code nicer when using curl_multi_socket() you can now check
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for CURLM_CALL_MULTI_SOCKET too in the same style it works for
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curl_multi_perform() and CURLM_CALL_MULTI_PERFORM */
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#define CURLM_CALL_MULTI_SOCKET CURLM_CALL_MULTI_PERFORM
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CURLMSG_NONE, /* first, not used */
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CURLMSG_DONE, /* This easy handle has completed. 'result' contains
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the CURLcode of the transfer */
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CURLMSG_LAST /* last, not used */
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CURLMSG msg; /* what this message means */
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CURL *easy_handle; /* the handle it concerns */
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void *whatever; /* message-specific data */
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CURLcode result; /* return code for transfer */
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typedef struct CURLMsg CURLMsg;
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* Name: curl_multi_init()
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* Desc: inititalize multi-style curl usage
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* Returns: a new CURLM handle to use in all 'curl_multi' functions.
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CURL_EXTERN CURLM *curl_multi_init(void);
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* Name: curl_multi_add_handle()
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* Desc: add a standard curl handle to the multi stack
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* Returns: CURLMcode type, general multi error code.
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CURL_EXTERN CURLMcode curl_multi_add_handle(CURLM *multi_handle,
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* Name: curl_multi_remove_handle()
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* Desc: removes a curl handle from the multi stack again
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* Returns: CURLMcode type, general multi error code.
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CURL_EXTERN CURLMcode curl_multi_remove_handle(CURLM *multi_handle,
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* Name: curl_multi_fdset()
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* Desc: Ask curl for its fd_set sets. The app can use these to select() or
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* poll() on. We want curl_multi_perform() called as soon as one of
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* Returns: CURLMcode type, general multi error code.
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CURL_EXTERN CURLMcode curl_multi_fdset(CURLM *multi_handle,
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fd_set *write_fd_set,
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* Name: curl_multi_perform()
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* Desc: When the app thinks there's data available for curl it calls this
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* function to read/write whatever there is right now. This returns
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* as soon as the reads and writes are done. This function does not
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* require that there actually is data available for reading or that
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* data can be written, it can be called just in case. It returns
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* the number of handles that still transfer data in the second
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* argument's integer-pointer.
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* Returns: CURLMcode type, general multi error code. *NOTE* that this only
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* returns errors etc regarding the whole multi stack. There might
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* still have occurred problems on invidual transfers even when this
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CURL_EXTERN CURLMcode curl_multi_perform(CURLM *multi_handle,
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int *running_handles);
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* Name: curl_multi_cleanup()
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* Desc: Cleans up and removes a whole multi stack. It does not free or
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* touch any individual easy handles in any way. We need to define
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* in what state those handles will be if this function is called
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* in the middle of a transfer.
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* Returns: CURLMcode type, general multi error code.
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CURL_EXTERN CURLMcode curl_multi_cleanup(CURLM *multi_handle);
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* Name: curl_multi_info_read()
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* Desc: Ask the multi handle if there's any messages/informationals from
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* the individual transfers. Messages include informationals such as
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* error code from the transfer or just the fact that a transfer is
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* completed. More details on these should be written down as well.
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* Repeated calls to this function will return a new struct each
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* time, until a special "end of msgs" struct is returned as a signal
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* that there is no more to get at this point.
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* The data the returned pointer points to will not survive calling
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* curl_multi_cleanup().
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* The 'CURLMsg' struct is meant to be very simple and only contain
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* very basic informations. If more involved information is wanted,
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* we will provide the particular "transfer handle" in that struct
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* and that should/could/would be used in subsequent
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* curl_easy_getinfo() calls (or similar). The point being that we
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* must never expose complex structs to applications, as then we'll
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* undoubtably get backwards compatibility problems in the future.
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* Returns: A pointer to a filled-in struct, or NULL if it failed or ran out
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* of structs. It also writes the number of messages left in the
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* queue (after this read) in the integer the second argument points
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CURL_EXTERN CURLMsg *curl_multi_info_read(CURLM *multi_handle,
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* Name: curl_multi_strerror()
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* Desc: The curl_multi_strerror function may be used to turn a CURLMcode
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* value into the equivalent human readable error string. This is
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* useful for printing meaningful error messages.
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* Returns: A pointer to a zero-terminated error message.
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CURL_EXTERN const char *curl_multi_strerror(CURLMcode);
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* Name: curl_multi_socket() and
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* curl_multi_socket_all()
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* Desc: An alternative version of curl_multi_perform() that allows the
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* application to pass in one of the file descriptors that have been
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* detected to have "action" on them and let libcurl perform.
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* See man page for details.
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#define CURL_POLL_NONE 0
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#define CURL_POLL_IN 1
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#define CURL_POLL_OUT 2
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#define CURL_POLL_INOUT 3
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#define CURL_POLL_REMOVE 4
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#define CURL_SOCKET_TIMEOUT CURL_SOCKET_BAD
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#define CURL_CSELECT_IN 0x01
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#define CURL_CSELECT_OUT 0x02
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#define CURL_CSELECT_ERR 0x04
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typedef int (*curl_socket_callback)(CURL *easy, /* easy handle */
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curl_socket_t s, /* socket */
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int what, /* see above */
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void *userp, /* private callback
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void *socketp); /* private socket
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* Name: curl_multi_timer_callback
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* Desc: Called by libcurl whenever the library detects a change in the
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* maximum number of milliseconds the app is allowed to wait before
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* curl_multi_socket() or curl_multi_perform() must be called
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* (to allow libcurl's timed events to take place).
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* Returns: The callback should return zero.
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typedef int (*curl_multi_timer_callback)(CURLM *multi, /* multi handle */
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long timeout_ms, /* see above */
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void *userp); /* private callback
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CURL_EXTERN CURLMcode curl_multi_socket(CURLM *multi_handle, curl_socket_t s,
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int *running_handles);
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CURL_EXTERN CURLMcode curl_multi_socket_action(CURLM *multi_handle,
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int *running_handles);
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CURL_EXTERN CURLMcode curl_multi_socket_all(CURLM *multi_handle,
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int *running_handles);
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#ifndef CURL_ALLOW_OLD_MULTI_SOCKET
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/* This macro below was added in 7.16.3 to push users who recompile to use
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the new curl_multi_socket_action() instead of the old curl_multi_socket()
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#define curl_multi_socket(x,y,z) curl_multi_socket_action(x,y,0,z)
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* Name: curl_multi_timeout()
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* Desc: Returns the maximum number of milliseconds the app is allowed to
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* wait before curl_multi_socket() or curl_multi_perform() must be
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* called (to allow libcurl's timed events to take place).
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* Returns: CURLM error code.
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CURL_EXTERN CURLMcode curl_multi_timeout(CURLM *multi_handle,
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#undef CINIT /* re-using the same name as in curl.h */
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#define CINIT(name,type,number) CURLMOPT_ ## name = CURLOPTTYPE_ ## type + number
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/* The macro "##" is ISO C, we assume pre-ISO C doesn't support it. */
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#define LONG CURLOPTTYPE_LONG
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#define OBJECTPOINT CURLOPTTYPE_OBJECTPOINT
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#define FUNCTIONPOINT CURLOPTTYPE_FUNCTIONPOINT
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#define OFF_T CURLOPTTYPE_OFF_T
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#define CINIT(name,type,number) CURLMOPT_/**/name = type + number
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/* This is the socket callback function pointer */
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CINIT(SOCKETFUNCTION, FUNCTIONPOINT, 1),
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/* This is the argument passed to the socket callback */
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CINIT(SOCKETDATA, OBJECTPOINT, 2),
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/* set to 1 to enable pipelining for this multi handle */
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CINIT(PIPELINING, LONG, 3),
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/* This is the timer callback function pointer */
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CINIT(TIMERFUNCTION, FUNCTIONPOINT, 4),
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/* This is the argument passed to the timer callback */
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CINIT(TIMERDATA, OBJECTPOINT, 5),
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/* maximum number of entries in the connection cache */
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CINIT(MAXCONNECTS, LONG, 6),
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CURLMOPT_LASTENTRY /* the last unused */
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* Name: curl_multi_setopt()
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* Desc: Sets options for the multi handle.
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* Returns: CURLM error code.
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CURL_EXTERN CURLMcode curl_multi_setopt(CURLM *multi_handle,
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CURLMoption option, ...);
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* Name: curl_multi_assign()
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* Desc: This function sets an association in the multi handle between the
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* given socket and a private pointer of the application. This is
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* (only) useful for curl_multi_socket uses.
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* Returns: CURLM error code.
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CURL_EXTERN CURLMcode curl_multi_assign(CURLM *multi_handle,
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curl_socket_t sockfd, void *sockp);
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} /* end of extern "C" */