docs/examples/multi-app.c

/***************************************************************************
 *                                  _   _ ____  _
 *  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
 *
 ***************************************************************************/
/* <DESC>
 * A basic application source code using the multi interface doing two
 * transfers in parallel.
 * </DESC>
 */
#include <stdio.h>
#include <string.h>

#include <curl/curl.h>

/*
 * Download an HTTP file and upload an FTP file simultaneously.
 */

#define HTTP_HANDLE 0   /* Index for the HTTP transfer */
#define FTP_HANDLE  1   /* Index for the FTP transfer */
#define HANDLECOUNT 2   /* Number of simultaneous transfers */

int main(void)
{
  CURL *curl[HANDLECOUNT];
  CURLM *multi;

  int i;

  CURLcode result = curl_global_init(CURL_GLOBAL_ALL);
  if(result != CURLE_OK)
    return (int)result;

  /* Allocate one curl handle per transfer */
  for(i = 0; i < HANDLECOUNT; i++)
    curl[i] = curl_easy_init();

  /* set the options (I left out a few, you get the point anyway) */
  curl_easy_setopt(curl[HTTP_HANDLE], CURLOPT_URL, "https://example.com");

  curl_easy_setopt(curl[FTP_HANDLE], CURLOPT_URL, "ftp://example.com");
  curl_easy_setopt(curl[FTP_HANDLE], CURLOPT_UPLOAD, 1L);

  /* init a multi stack */
  multi = curl_multi_init();
  if(multi) {

    int still_running = 1; /* keep number of running handles */

    CURLMsg *msg;  /* for picking up messages with the transfer status */
    int msgs_left; /* how many messages are left */

    /* add the individual transfers */
    for(i = 0; i < HANDLECOUNT; i++)
      curl_multi_add_handle(multi, curl[i]);

    while(still_running) {
      CURLMcode mresult = curl_multi_perform(multi, &still_running);

      if(still_running)
        /* wait for activity, timeout or "nothing" */
        mresult = curl_multi_poll(multi, NULL, 0, 1000, NULL);

      if(mresult)
        break;
    }

    /* See how the transfers went */
    /* !checksrc! disable EQUALSNULL 1 */
    while((msg = curl_multi_info_read(multi, &msgs_left)) != NULL) {
      if(msg->msg == CURLMSG_DONE) {
        int idx;

        /* Find out which handle this message is about */
        for(idx = 0; idx < HANDLECOUNT; idx++) {
          int found = (msg->easy_handle == curl[idx]);
          if(found)
            break;
        }

        switch(idx) {
        case HTTP_HANDLE:
          printf("HTTP transfer completed with status %d\n",
                 (int)msg->data.result);
          break;
        case FTP_HANDLE:
          printf("FTP transfer completed with status %d\n",
                 (int)msg->data.result);
          break;
        }
      }
    }

    /* remove the transfers */
    for(i = 0; i < HANDLECOUNT; i++)
      curl_multi_remove_handle(multi, curl[i]);

    curl_multi_cleanup(multi);
  }

  /* Free the curl handles */
  for(i = 0; i < HANDLECOUNT; i++)
    curl_easy_cleanup(curl[i]);

  curl_global_cleanup();

  return 0;
}