3 /***************************************************************************
5 * Project ___| | | | _ \| |
7 * | (__| |_| | _ <| |___
8 * \___|\___/|_| \_\_____|
10 * Copyright (C) 1998 - 2005, Daniel Stenberg, <daniel@haxx.se>, et al.
12 * This software is licensed as described in the file COPYING, which
13 * you should have received as part of this distribution. The terms
14 * are also available at http://curl.haxx.se/docs/copyright.html.
16 * You may opt to use, copy, modify, merge, publish, distribute and/or sell
17 * copies of the Software, and permit persons to whom the Software is
18 * furnished to do so, under the terms of the COPYING file.
20 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
21 * KIND, either express or implied.
23 * $Id: multi.h,v 1.1 2006/07/09 22:41:14 fred_t_hamster Exp $
24 ***************************************************************************/
26 This is an "external" header file. Don't give away any internals here!
30 o Enable a "pull" interface. The application that uses libcurl decides where
31 and when to ask libcurl to get/send data.
33 o Enable multiple simultaneous transfers in the same thread without making it
34 complicated for the application.
36 o Enable the application to select() on its own file descriptors and curl's
37 file descriptors simultaneous easily.
40 #if defined(_WIN32) && !defined(WIN32)
41 /* Chris Lewis mentioned that he doesn't get WIN32 defined, only _WIN32 so we
42 make this adjustment to catch this. */
46 #if defined(WIN32) && !defined(_WIN32_WCE) && !defined(__GNUC__) || \
48 #if !(defined(_WINSOCKAPI_) || defined(_WINSOCK_H))
49 /* The check above prevents the winsock2 inclusion if winsock.h already was
50 included, since they can't co-exist without problems */
55 /* HP-UX systems version 9, 10 and 11 lack sys/select.h and so does oldish
56 libc5-based Linux systems. Only include it on system that are known to
58 #if defined(_AIX) || defined(NETWARE)
59 #include <sys/select.h>
63 #include <sys/socket.h>
66 #include <sys/types.h>
70 * This header file should not really need to include "curl.h" since curl.h
71 * itself includes this file and we expect user applications to do #include
72 * <curl/curl.h> without the need for especially including multi.h.
74 * For some reason we added this include here at one point, and rather than to
75 * break existing (wrongly written) libcurl applications, we leave it as-is
76 * but with this warning attached.
86 #ifdef HAVE_CURL_MULTI_SOCKET /* this is not set by anything yet */
88 #ifndef curl_socket_typedef
89 /* Public socket typedef */
91 typedef SOCKET curl_socket_t;
92 #define CURL_SOCKET_BAD INVALID_SOCKET
94 typedef int curl_socket_t;
95 #define CURL_SOCKET_BAD -1
97 #define curl_socket_typedef
98 #endif /* curl_socket_typedef */
100 #endif /* HAVE_CURL_MULTI_SOCKET */
103 CURLM_CALL_MULTI_PERFORM = -1, /* please call curl_multi_perform() soon */
105 CURLM_BAD_HANDLE, /* the passed-in handle is not a valid CURLM handle */
106 CURLM_BAD_EASY_HANDLE, /* an easy handle was not good/valid */
107 CURLM_OUT_OF_MEMORY, /* if you ever get this, you're in deep sh*t */
108 CURLM_INTERNAL_ERROR, /* this is a libcurl bug */
113 CURLMSG_NONE, /* first, not used */
114 CURLMSG_DONE, /* This easy handle has completed. 'result' contains
115 the CURLcode of the transfer */
116 CURLMSG_LAST /* last, not used */
120 CURLMSG msg; /* what this message means */
121 CURL *easy_handle; /* the handle it concerns */
123 void *whatever; /* message-specific data */
124 CURLcode result; /* return code for transfer */
127 typedef struct CURLMsg CURLMsg;
130 * Name: curl_multi_init()
132 * Desc: inititalize multi-style curl usage
134 * Returns: a new CURLM handle to use in all 'curl_multi' functions.
136 CURL_EXTERN CURLM *curl_multi_init(void);
139 * Name: curl_multi_add_handle()
141 * Desc: add a standard curl handle to the multi stack
143 * Returns: CURLMcode type, general multi error code.
145 CURL_EXTERN CURLMcode curl_multi_add_handle(CURLM *multi_handle,
149 * Name: curl_multi_remove_handle()
151 * Desc: removes a curl handle from the multi stack again
153 * Returns: CURLMcode type, general multi error code.
155 CURL_EXTERN CURLMcode curl_multi_remove_handle(CURLM *multi_handle,
159 * Name: curl_multi_fdset()
161 * Desc: Ask curl for its fd_set sets. The app can use these to select() or
162 * poll() on. We want curl_multi_perform() called as soon as one of
165 * Returns: CURLMcode type, general multi error code.
167 CURL_EXTERN CURLMcode curl_multi_fdset(CURLM *multi_handle,
169 fd_set *write_fd_set,
174 * Name: curl_multi_perform()
176 * Desc: When the app thinks there's data available for curl it calls this
177 * function to read/write whatever there is right now. This returns
178 * as soon as the reads and writes are done. This function does not
179 * require that there actually is data available for reading or that
180 * data can be written, it can be called just in case. It returns
181 * the number of handles that still transfer data in the second
182 * argument's integer-pointer.
184 * Returns: CURLMcode type, general multi error code. *NOTE* that this only
185 * returns errors etc regarding the whole multi stack. There might
186 * still have occurred problems on invidual transfers even when this
189 CURL_EXTERN CURLMcode curl_multi_perform(CURLM *multi_handle,
190 int *running_handles);
193 * Name: curl_multi_cleanup()
195 * Desc: Cleans up and removes a whole multi stack. It does not free or
196 * touch any individual easy handles in any way. We need to define
197 * in what state those handles will be if this function is called
198 * in the middle of a transfer.
200 * Returns: CURLMcode type, general multi error code.
202 CURL_EXTERN CURLMcode curl_multi_cleanup(CURLM *multi_handle);
205 * Name: curl_multi_info_read()
207 * Desc: Ask the multi handle if there's any messages/informationals from
208 * the individual transfers. Messages include informationals such as
209 * error code from the transfer or just the fact that a transfer is
210 * completed. More details on these should be written down as well.
212 * Repeated calls to this function will return a new struct each
213 * time, until a special "end of msgs" struct is returned as a signal
214 * that there is no more to get at this point.
216 * The data the returned pointer points to will not survive calling
217 * curl_multi_cleanup().
219 * The 'CURLMsg' struct is meant to be very simple and only contain
220 * very basic informations. If more involved information is wanted,
221 * we will provide the particular "transfer handle" in that struct
222 * and that should/could/would be used in subsequent
223 * curl_easy_getinfo() calls (or similar). The point being that we
224 * must never expose complex structs to applications, as then we'll
225 * undoubtably get backwards compatibility problems in the future.
227 * Returns: A pointer to a filled-in struct, or NULL if it failed or ran out
228 * of structs. It also writes the number of messages left in the
229 * queue (after this read) in the integer the second argument points
232 CURL_EXTERN CURLMsg *curl_multi_info_read(CURLM *multi_handle,
236 * Name: curl_multi_strerror()
238 * Desc: The curl_multi_strerror function may be used to turn a CURLMcode
239 * value into the equivalent human readable error string. This is
240 * useful for printing meaningful error messages.
242 * Returns: A pointer to a zero-terminated error message.
244 CURL_EXTERN const char *curl_multi_strerror(CURLMcode);
246 #ifdef HAVE_CURL_MULTI_SOCKET
248 * Name: curl_multi_socket() and
249 * curl_multi_socket_all()
251 * Desc: An alternative version of curl_multi_perform() that allows the
252 * application to pass in one of the file descriptors that have been
253 * detected to have "action" on them and let libcurl perform. This
254 * allows libcurl to not have to scan through all possible file
255 * descriptors to check for this. The app is recommended to pass in
256 * the 'easy' argument (or set it to CURL_EASY_NONE) to make libcurl
257 * figure out the internal structure even faster and easier. If the
258 * easy argument is set to something else than CURL_EASY_NONE, the
259 * 's' (socket) argument will be ignored by libcurl.
261 * It also informs the application about updates in the socket (file
262 * descriptor) status by doing none, one or multiple calls to the
263 * curl_socket_callback. It thus updates the status with changes
264 * since the previous time this function was used. If 'callback' is
265 * NULL, no callback will be called. A status change may also be a
266 * new timeout only, having the same IN/OUT status as before.
268 * If a previous wait for socket action(s) timed out, you should call
269 * this function with the socket argument set to
270 * CURL_SOCKET_TIMEOUT. If you want to force libcurl to (re-)check
271 * all its internal sockets, and call the callback with status for
272 * all sockets no matter what the previous state is, you call
273 * curl_multi_socket_all() instead.
275 * curl_multi_perform() is thus the equivalent of calling
276 * curl_multi_socket_all(handle, NULL, NULL);
278 * IMPLEMENTATION: libcurl will need an internal hash table to map
279 * socket numbers to internal easy handles for the cases when 'easy'
280 * is set to CURL_EASY_NONE.
282 * Regarding the timeout argument in the callback: it is the timeout
283 * (in milliseconds) for waiting on action on this socket (and the
284 * given time period starts when the callback is called) until you
285 * should call curl_multi_socket() with the timeout stuff mentioned
286 * above. If "actions" happens on the socket before the timeout
287 * happens, remember that the timout timer keeps ticking until told
290 * The "what" argument has one of five values:
292 * 0 CURL_POLL_NONE (0) - register, not interested in readiness
293 * 1 CURL_POLL_IN - register, interested in read readiness
294 * 2 CURL_POLL_OUT - register, interested in write readiness
295 * 3 CURL_POLL_INOUT - register, interested in both
296 * 4 CURL_POLL_REMOVE - deregister
298 #define CURL_POLL_NONE 0
299 #define CURL_POLL_IN 1
300 #define CURL_POLL_OUT 2
301 #define CURL_POLL_INOUT 3
302 #define CURL_POLL_REMOVE 4
304 #define CURL_EASY_NONE (CURL *)0
305 #define CURL_EASY_TIMEOUT (CURL *)0
306 #define CURL_SOCKET_TIMEOUT CURL_SOCKET_BAD
308 typedef int (*curl_socket_callback)(CURL *easy, /* easy handle */
309 curl_socket_t s, /* socket */
310 int what, /* see above */
311 long ms, /* timeout for wait */
312 void *userp); /* "private" pointer */
314 CURLMcode curl_multi_socket(CURLM *multi_handle,
317 curl_socket_callback callback,
318 void *userp); /* passed to callback */
320 CURLMcode curl_multi_socket_all(CURLM *multi_handle,
321 curl_socket_callback callback,
322 void *userp); /* passed to callback */
325 * Name: curl_multi_timeout()
327 * Desc: Returns the maximum number of milliseconds the app is allowed to
328 * wait before curl_multi_socket() or curl_multi_perform() must be
329 * called (to allow libcurl's timed events to take place).
331 * Returns: CURLM error code.
333 CURLMcode curl_multi_timeout(CURLM *multi_handle, long *milliseconds);
335 #endif /* HAVE_CURL_MULTI_SOCKET */
338 } /* end of extern "C" */