#ifndef __CURL_MULTI_H #define __CURL_MULTI_H /*************************************************************************** * _ _ ____ _ * Project ___| | | | _ \| | * / __| | | | |_) | | * | (__| |_| | _ <| |___ * \___|\___/|_| \_\_____| * * Copyright (C) 1998 - 2002, 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. * * $Id: multi.h,v 1.1.1.1 2002/11/26 19:07:47 zarzycki Exp $ ***************************************************************************/ /* This is meant to be the "external" header file. Don't give away any internals here! This document presents a mixture of ideas from at least: - Daniel Stenberg - Steve Dekorte - Sterling Hughes - Ben Greear ------------------------------------------- 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. Example sources using this interface is here: ../multi/ */ #if defined(WIN32) && !defined(__GNUC__) || defined(__MINGW32__) #include <winsock.h> #else #include <sys/socket.h> #include <sys/time.h> #endif #include "curl.h" typedef void CURLM; typedef enum { CURLM_CALL_MULTI_PERFORM=-1, /* please call curl_multi_perform() 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're in deep sh*t */ CURLM_INTERNAL_ERROR, /* this is a libcurl bug */ CURLM_LAST } CURLMcode; typedef enum { CURLMSG_NONE, /* first, not used */ CURLMSG_DONE, /* This easy handle has completed. 'whatever' points to 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; /* * Name: curl_multi_init() * * Desc: inititalize multi-style curl usage * Returns: a new CURLM handle to use in all 'curl_multi' functions. */ 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. */ 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. */ 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. */ 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_perform() * * Desc: When the app thinks there's 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 invidual transfers even when this * returns OK. */ 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. */ CURLMcode curl_multi_cleanup(CURLM *multi_handle); /* * Name: curl_multi_info_read() * * Desc: Ask the multi handle if there's 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 very simple and only contain * very basic informations. 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'll * 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. */ CURLMsg *curl_multi_info_read(CURLM *multi_handle, int *msgs_in_queue); #endif