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 #ifndef CURLINC_MULTI_H
 #define CURLINC_MULTI_H
 /***************************************************************************
  *                                  _   _ ____  _
  *  Project                     ___| | | |  _ \| |
  *                             / __| | | | |_) | |
  *                            | (__| |_| |  _ <| |___
  *                             \___|\___/|_| \_\_____|
  *
  * Copyright (C) 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 https://curl.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.
  *
  * SPDX-License-Identifier: curl
  *
  ***************************************************************************/
 /*
   This is an "external" header file. Do not give away any internals here!
 
   GOALS
 
   o Enable a "pull" interface. The application that uses libcurl decides where
     and when to ask libcurl to get/send data.
 
   o Enable multiple simultaneous transfers in the same thread without making it
     complicated for the application.
 
   o Enable the application to select() on its own file descriptors and curl's
     file descriptors simultaneous easily.
 
 */
 
 /*
  * This header file should not really need to include "curl.h" since curl.h
  * itself includes this file and we expect user applications to do #include
  * <curl/curl.h> without the need for especially including multi.h.
  *
  * For some reason we added this include here at one point, and rather than to
  * break existing (wrongly written) libcurl applications, we leave it as-is
  * but with this warning attached.
  */
 #include "curl.h"
 
 #ifdef __cplusplus
 extern "C" {
 #endif
 
 typedef void CURLM;
 
 typedef enum {
   CURLM_CALL_MULTI_PERFORM = -1, /* please call curl_multi_perform() or
                                     curl_multi_socket*() soon */
   CURLM_OK,
   CURLM_BAD_HANDLE,      /* the passed-in handle is not a valid CURLM handle */
   CURLM_BAD_EASY_HANDLE, /* an easy handle was not good/valid */
   CURLM_OUT_OF_MEMORY,   /* if you ever get this, you are in deep sh*t */
   CURLM_INTERNAL_ERROR,  /* this is a libcurl bug */
   CURLM_BAD_SOCKET,      /* the passed in socket argument did not match */
   CURLM_UNKNOWN_OPTION,  /* curl_multi_setopt() with unsupported option */
   CURLM_ADDED_ALREADY,   /* an easy handle already added to a multi handle was
                             attempted to get added - again */
   CURLM_RECURSIVE_API_CALL, /* an api function was called from inside a
                                callback */
   CURLM_WAKEUP_FAILURE,  /* wakeup is unavailable or failed */
   CURLM_BAD_FUNCTION_ARGUMENT, /* function called with a bad parameter */
   CURLM_ABORTED_BY_CALLBACK,
   CURLM_UNRECOVERABLE_POLL,
   CURLM_LAST
 } CURLMcode;
 
 /* just to make code nicer when using curl_multi_socket() you can now check
    for CURLM_CALL_MULTI_SOCKET too in the same style it works for
    curl_multi_perform() and CURLM_CALL_MULTI_PERFORM */
 #define CURLM_CALL_MULTI_SOCKET CURLM_CALL_MULTI_PERFORM
 
 /* bitmask bits for CURLMOPT_PIPELINING */
 #define CURLPIPE_NOTHING   0L
 #define CURLPIPE_HTTP1     1L
 #define CURLPIPE_MULTIPLEX 2L
 
 typedef enum {
   CURLMSG_NONE, /* first, not used */
   CURLMSG_DONE, /* This easy handle has completed. 'result' contains
                    the CURLcode of the transfer */
   CURLMSG_LAST /* last, not used */
 } CURLMSG;
 
 struct CURLMsg {
   CURLMSG msg;       /* what this message means */
   CURL *easy_handle; /* the handle it concerns */
   union {
     void *whatever;    /* message-specific data */
     CURLcode result;   /* return code for transfer */
   } data;
 };
 typedef struct CURLMsg CURLMsg;
 
 /* Based on poll(2) structure and values.
  * We do not use pollfd and POLL* constants explicitly
  * to cover platforms without poll(). */
 #define CURL_WAIT_POLLIN    0x0001
 #define CURL_WAIT_POLLPRI   0x0002
 #define CURL_WAIT_POLLOUT   0x0004
 
 struct curl_waitfd {
   curl_socket_t fd;
   short events;
   short revents;
 };
 
 /*
  * Name:    curl_multi_init()
  *
  * Desc:    initialize multi-style curl usage
  *
  * Returns: a new CURLM handle to use in all 'curl_multi' functions.
  */
 CURL_EXTERN CURLM *curl_multi_init(void);
 
 /*
  * Name:    curl_multi_add_handle()
  *
  * Desc:    add a standard curl handle to the multi stack
  *
  * Returns: CURLMcode type, general multi error code.
  */
 CURL_EXTERN CURLMcode curl_multi_add_handle(CURLM *multi_handle,
                                             CURL *curl_handle);
 
 /*
  * Name:    curl_multi_remove_handle()
  *
  * Desc:    removes a curl handle from the multi stack again
  *
  * Returns: CURLMcode type, general multi error code.
  */
 CURL_EXTERN CURLMcode curl_multi_remove_handle(CURLM *multi_handle,
                                                CURL *curl_handle);
 
 /*
  * Name:    curl_multi_fdset()
  *
  * Desc:    Ask curl for its fd_set sets. The app can use these to select() or
  *          poll() on. We want curl_multi_perform() called as soon as one of
  *          them are ready.
  *
  * Returns: CURLMcode type, general multi error code.
  */
 CURL_EXTERN CURLMcode curl_multi_fdset(CURLM *multi_handle,
                                        fd_set *read_fd_set,
                                        fd_set *write_fd_set,
                                        fd_set *exc_fd_set,
                                        int *max_fd);
 
 /*
  * Name:     curl_multi_wait()
  *
  * Desc:     Poll on all fds within a CURLM set as well as any
  *           additional fds passed to the function.
  *
  * Returns:  CURLMcode type, general multi error code.
  */
 CURL_EXTERN CURLMcode curl_multi_wait(CURLM *multi_handle,
                                       struct curl_waitfd extra_fds[],
                                       unsigned int extra_nfds,
                                       int timeout_ms,
                                       int *ret);
 
 /*
  * Name:     curl_multi_poll()
  *
  * Desc:     Poll on all fds within a CURLM set as well as any
  *           additional fds passed to the function.
  *
  * Returns:  CURLMcode type, general multi error code.
  */
 CURL_EXTERN CURLMcode curl_multi_poll(CURLM *multi_handle,
                                       struct curl_waitfd extra_fds[],
                                       unsigned int extra_nfds,
                                       int timeout_ms,
                                       int *ret);
 
 /*
  * Name:     curl_multi_wakeup()
  *
  * Desc:     wakes up a sleeping curl_multi_poll call.
  *
  * Returns:  CURLMcode type, general multi error code.
  */
 CURL_EXTERN CURLMcode curl_multi_wakeup(CURLM *multi_handle);
 
 /*
  * Name:    curl_multi_perform()
  *
  * Desc:    When the app thinks there is data available for curl it calls this
  *          function to read/write whatever there is right now. This returns
  *          as soon as the reads and writes are done. This function does not
  *          require that there actually is data available for reading or that
  *          data can be written, it can be called just in case. It returns
  *          the number of handles that still transfer data in the second
  *          argument's integer-pointer.
  *
  * Returns: CURLMcode type, general multi error code. *NOTE* that this only
  *          returns errors etc regarding the whole multi stack. There might
  *          still have occurred problems on individual transfers even when
  *          this returns OK.
  */
 CURL_EXTERN CURLMcode curl_multi_perform(CURLM *multi_handle,
                                          int *running_handles);
 
 /*
  * Name:    curl_multi_cleanup()
  *
  * Desc:    Cleans up and removes a whole multi stack. It does not free or
  *          touch any individual easy handles in any way. We need to define
  *          in what state those handles will be if this function is called
  *          in the middle of a transfer.
  *
  * Returns: CURLMcode type, general multi error code.
  */
 CURL_EXTERN CURLMcode curl_multi_cleanup(CURLM *multi_handle);
 
 /*
  * Name:    curl_multi_info_read()
  *
  * Desc:    Ask the multi handle if there is any messages/informationals from
  *          the individual transfers. Messages include informationals such as
  *          error code from the transfer or just the fact that a transfer is
  *          completed. More details on these should be written down as well.
  *
  *          Repeated calls to this function will return a new struct each
  *          time, until a special "end of msgs" struct is returned as a signal
  *          that there is no more to get at this point.
  *
  *          The data the returned pointer points to will not survive calling
  *          curl_multi_cleanup().
  *
  *          The 'CURLMsg' struct is meant to be simple and only contain basic
  *          information. If more involved information is wanted, we will
  *          provide the particular "transfer handle" in that struct and that
  *          should/could/would be used in subsequent curl_easy_getinfo() calls
  *          (or similar). The point being that we must never expose complex
  *          structs to applications, as then we will undoubtably get backwards
  *          compatibility problems in the future.
  *
  * Returns: A pointer to a filled-in struct, or NULL if it failed or ran out
  *          of structs. It also writes the number of messages left in the
  *          queue (after this read) in the integer the second argument points
  *          to.
  */
 CURL_EXTERN CURLMsg *curl_multi_info_read(CURLM *multi_handle,
                                           int *msgs_in_queue);
 
 /*
  * Name:    curl_multi_strerror()
  *
  * Desc:    The curl_multi_strerror function may be used to turn a CURLMcode
  *          value into the equivalent human readable error string. This is
  *          useful for printing meaningful error messages.
  *
  * Returns: A pointer to a null-terminated error message.
  */
 CURL_EXTERN const char *curl_multi_strerror(CURLMcode);
 
 /*
  * Name:    curl_multi_socket() and
  *          curl_multi_socket_all()
  *
  * Desc:    An alternative version of curl_multi_perform() that allows the
  *          application to pass in one of the file descriptors that have been
  *          detected to have "action" on them and let libcurl perform.
  *          See man page for details.
  */
 #define CURL_POLL_NONE   0
 #define CURL_POLL_IN     1
 #define CURL_POLL_OUT    2
 #define CURL_POLL_INOUT  3
 #define CURL_POLL_REMOVE 4
 
 #define CURL_SOCKET_TIMEOUT CURL_SOCKET_BAD
 
 #define CURL_CSELECT_IN   0x01
 #define CURL_CSELECT_OUT  0x02
 #define CURL_CSELECT_ERR  0x04
 
 typedef int (*curl_socket_callback)(CURL *easy,      /* easy handle */
                                     curl_socket_t s, /* socket */
                                     int what,        /* see above */
                                     void *userp,     /* private callback
                                                         pointer */
                                     void *socketp);  /* private socket
                                                         pointer */
 /*
  * Name:    curl_multi_timer_callback
  *
  * Desc:    Called by libcurl whenever the library detects a change in the
  *          maximum number of milliseconds the app is allowed to wait before
  *          curl_multi_socket() or curl_multi_perform() must be called
  *          (to allow libcurl's timed events to take place).
  *
  * Returns: The callback should return zero.
  */
 typedef int (*curl_multi_timer_callback)(CURLM *multi,    /* multi handle */
                                          long timeout_ms, /* see above */
                                          void *userp);    /* private callback
                                                              pointer */
 
 CURL_EXTERN CURLMcode CURL_DEPRECATED(7.19.5, "Use curl_multi_socket_action()")
 curl_multi_socket(CURLM *multi_handle, curl_socket_t s, int *running_handles);
 
 CURL_EXTERN CURLMcode curl_multi_socket_action(CURLM *multi_handle,
                                                curl_socket_t s,
                                                int ev_bitmask,
                                                int *running_handles);
 
 CURL_EXTERN CURLMcode CURL_DEPRECATED(7.19.5, "Use curl_multi_socket_action()")
 curl_multi_socket_all(CURLM *multi_handle, int *running_handles);
 
 #ifndef CURL_ALLOW_OLD_MULTI_SOCKET
 /* This macro below was added in 7.16.3 to push users who recompile to use
  * the new curl_multi_socket_action() instead of the old curl_multi_socket()
  */
 #define curl_multi_socket(x,y,z) curl_multi_socket_action(x,y,0,z)
 #endif
 
 /*
  * Name:    curl_multi_timeout()
  *
  * Desc:    Returns the maximum number of milliseconds the app is allowed to
  *          wait before curl_multi_socket() or curl_multi_perform() must be
  *          called (to allow libcurl's timed events to take place).
  *
  * Returns: CURLM error code.
  */
 CURL_EXTERN CURLMcode curl_multi_timeout(CURLM *multi_handle,
                                          long *milliseconds);
 
 typedef enum {
   /* This is the socket callback function pointer */
   CURLOPT(CURLMOPT_SOCKETFUNCTION, CURLOPTTYPE_FUNCTIONPOINT, 1),
 
   /* This is the argument passed to the socket callback */
   CURLOPT(CURLMOPT_SOCKETDATA, CURLOPTTYPE_OBJECTPOINT, 2),
 
   /* set to 1 to enable pipelining for this multi handle */
   CURLOPT(CURLMOPT_PIPELINING, CURLOPTTYPE_LONG, 3),
 
   /* This is the timer callback function pointer */
   CURLOPT(CURLMOPT_TIMERFUNCTION, CURLOPTTYPE_FUNCTIONPOINT, 4),
 
   /* This is the argument passed to the timer callback */
   CURLOPT(CURLMOPT_TIMERDATA, CURLOPTTYPE_OBJECTPOINT, 5),
 
   /* maximum number of entries in the connection cache */
   CURLOPT(CURLMOPT_MAXCONNECTS, CURLOPTTYPE_LONG, 6),
 
   /* maximum number of (pipelining) connections to one host */
   CURLOPT(CURLMOPT_MAX_HOST_CONNECTIONS, CURLOPTTYPE_LONG, 7),
 
   /* maximum number of requests in a pipeline */
   CURLOPT(CURLMOPT_MAX_PIPELINE_LENGTH, CURLOPTTYPE_LONG, 8),
 
   /* a connection with a content-length longer than this
      will not be considered for pipelining */
   CURLOPT(CURLMOPT_CONTENT_LENGTH_PENALTY_SIZE, CURLOPTTYPE_OFF_T, 9),
 
   /* a connection with a chunk length longer than this
      will not be considered for pipelining */
   CURLOPT(CURLMOPT_CHUNK_LENGTH_PENALTY_SIZE, CURLOPTTYPE_OFF_T, 10),
 
   /* a list of site names(+port) that are blocked from pipelining */
   CURLOPT(CURLMOPT_PIPELINING_SITE_BL, CURLOPTTYPE_OBJECTPOINT, 11),
 
   /* a list of server types that are blocked from pipelining */
   CURLOPT(CURLMOPT_PIPELINING_SERVER_BL, CURLOPTTYPE_OBJECTPOINT, 12),
 
   /* maximum number of open connections in total */
   CURLOPT(CURLMOPT_MAX_TOTAL_CONNECTIONS, CURLOPTTYPE_LONG, 13),
 
    /* This is the server push callback function pointer */
   CURLOPT(CURLMOPT_PUSHFUNCTION, CURLOPTTYPE_FUNCTIONPOINT, 14),
 
   /* This is the argument passed to the server push callback */
   CURLOPT(CURLMOPT_PUSHDATA, CURLOPTTYPE_OBJECTPOINT, 15),
 
   /* maximum number of concurrent streams to support on a connection */
   CURLOPT(CURLMOPT_MAX_CONCURRENT_STREAMS, CURLOPTTYPE_LONG, 16),
 
   /* network has changed, adjust caches/connection reuse */
   CURLOPT(CURLMOPT_NETWORK_CHANGED, CURLOPTTYPE_LONG, 17),
 
   /* This is the notify callback function pointer */
   CURLOPT(CURLMOPT_NOTIFYFUNCTION, CURLOPTTYPE_FUNCTIONPOINT, 18),
 
   /* This is the argument passed to the notify callback */
   CURLOPT(CURLMOPT_NOTIFYDATA, CURLOPTTYPE_OBJECTPOINT, 19),
 
   CURLMOPT_LASTENTRY /* the last unused */
 } CURLMoption;
 
 /* Definition of bits for the CURLMOPT_NETWORK_CHANGED argument: */
 
 /* - CURLMNWC_CLEAR_CONNS tells libcurl to prevent further reuse of existing
    connections. Connections that are idle will be closed. Ongoing transfers
    will continue with the connection they have. */
 #define CURLMNWC_CLEAR_CONNS (1L << 0)
 
 /* - CURLMNWC_CLEAR_DNS tells libcurl to prevent further reuse of existing
    connections. Connections that are idle will be closed. Ongoing transfers
    will continue with the connection they have. */
 #define CURLMNWC_CLEAR_DNS (1L << 0)
 
 /*
  * Name:    curl_multi_setopt()
  *
  * Desc:    Sets options for the multi handle.
  *
  * Returns: CURLM error code.
  */
 CURL_EXTERN CURLMcode curl_multi_setopt(CURLM *multi_handle,
                                         CURLMoption option, ...);
 
 /*
  * Name:    curl_multi_assign()
  *
  * Desc:    This function sets an association in the multi handle between the
  *          given socket and a private pointer of the application. This is
  *          (only) useful for curl_multi_socket uses.
  *
  * Returns: CURLM error code.
  */
 CURL_EXTERN CURLMcode curl_multi_assign(CURLM *multi_handle,
                                         curl_socket_t sockfd, void *sockp);
 
 /*
  * Name:    curl_multi_get_handles()
  *
  * Desc:    Returns an allocated array holding all handles currently added to
  *          the multi handle. Marks the final entry with a NULL pointer. If
  *          there is no easy handle added to the multi handle, this function
  *          returns an array with the first entry as a NULL pointer.
  *
  * Returns: NULL on failure, otherwise a CURL **array pointer
  */
 CURL_EXTERN CURL **curl_multi_get_handles(CURLM *multi_handle);
 
 typedef enum {
   CURLMINFO_NONE, /* first, never use this */
   /* The number of easy handles currently managed by the multi handle,
    * e.g. have been added but not yet removed. */
   CURLMINFO_XFERS_CURRENT = 1,
   /* The number of easy handles running, e.g. not done and not queueing. */
   CURLMINFO_XFERS_RUNNING = 2,
   /* The number of easy handles waiting to start, e.g. for a connection
    * to become available due to limits on parallelism, max connections
    * or other factors. */
   CURLMINFO_XFERS_PENDING = 3,
   /* The number of easy handles finished, waiting for their results to
    * be read via `curl_multi_info_read()`. */
   CURLMINFO_XFERS_DONE = 4,
   /* The total number of easy handles added to the multi handle, ever. */
   CURLMINFO_XFERS_ADDED = 5,
 
   CURLMINFO_LASTENTRY /* the last unused */
 } CURLMinfo_offt;
 
 /*
  * Name:    curl_multi_get_offt()
  *
  * Desc:    Retrieves a numeric value for the `CURLMINFO_*` enums.
  *
  * Returns: CULRM_OK or error when value could not be obtained.
  */
 CURL_EXTERN CURLMcode curl_multi_get_offt(CURLM *multi_handle,
                                           CURLMinfo_offt info,
                                           curl_off_t *pvalue);
 
 /*
  * Name: curl_push_callback
  *
  * Desc: This callback gets called when a new stream is being pushed by the
  *       server. It approves or denies the new stream. It can also decide
  *       to completely fail the connection.
  *
  * Returns: CURL_PUSH_OK, CURL_PUSH_DENY or CURL_PUSH_ERROROUT
  */
 #define CURL_PUSH_OK       0
 #define CURL_PUSH_DENY     1
 #define CURL_PUSH_ERROROUT 2 /* added in 7.72.0 */
 
 struct curl_pushheaders;  /* forward declaration only */
 
 CURL_EXTERN char *curl_pushheader_bynum(struct curl_pushheaders *h,
                                         size_t num);
 CURL_EXTERN char *curl_pushheader_byname(struct curl_pushheaders *h,
                                          const char *name);
 
 typedef int (*curl_push_callback)(CURL *parent,
                                   CURL *easy,
                                   size_t num_headers,
                                   struct curl_pushheaders *headers,
                                   void *userp);
 
 /*
  * Name:    curl_multi_waitfds()
  *
  * Desc:    Ask curl for fds for polling. The app can use these to poll on.
  *          We want curl_multi_perform() called as soon as one of them are
  *          ready. Passing zero size allows to get just a number of fds.
  *
  * Returns: CURLMcode type, general multi error code.
  */
 CURL_EXTERN CURLMcode curl_multi_waitfds(CURLM *multi,
                                          struct curl_waitfd *ufds,
                                          unsigned int size,
                                          unsigned int *fd_count);
 
 /*
  * Notifications dispatched by a multi handle, when enabled.
  */
 #define CURLMNOTIFY_INFO_READ    0
 #define CURLMNOTIFY_EASY_DONE    1
 
 /*
  * Callback to install via CURLMOPT_NOTIFYFUNCTION.
  */
 typedef void (*curl_notify_callback)(CURLM *multi,
                                      unsigned int notification,
                                      CURL *easy,
                                      void *user_data);
 
 CURL_EXTERN CURLMcode curl_multi_notify_disable(CURLM *multi,
                                                 unsigned int notification);
 
 CURL_EXTERN CURLMcode curl_multi_notify_enable(CURLM *multi,
                                                unsigned int notification);
 
 #ifdef __cplusplus
 } /* end of extern "C" */
 #endif
 
 #endif

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