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      1 /***************************************************************************
      2  *                                  _   _ ____  _
      3  *  Project                     ___| | | |  _ \| |
      4  *                             / __| | | | |_) | |
      5  *                            | (__| |_| |  _ <| |___
      6  *                             \___|\___/|_| \_\_____|
      7  *
      8  * Copyright (C) 1998 - 2013, Daniel Stenberg, <daniel (at) haxx.se>, et al.
      9  *
     10  * This software is licensed as described in the file COPYING, which
     11  * you should have received as part of this distribution. The terms
     12  * are also available at http://curl.haxx.se/docs/copyright.html.
     13  *
     14  * You may opt to use, copy, modify, merge, publish, distribute and/or sell
     15  * copies of the Software, and permit persons to whom the Software is
     16  * furnished to do so, under the terms of the COPYING file.
     17  *
     18  * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
     19  * KIND, either express or implied.
     20  *
     21  ***************************************************************************/
     22 #include <stdio.h>
     23 #include <stdlib.h>
     24 #include <string.h>
     25 #include <curl/curl.h>
     26 
     27 struct MemoryStruct {
     28   char *memory;
     29   size_t size;
     30 };
     31 
     32 static size_t
     33 WriteMemoryCallback(void *contents, size_t size, size_t nmemb, void *userp)
     34 {
     35   size_t realsize = size * nmemb;
     36   struct MemoryStruct *mem = (struct MemoryStruct *)userp;
     37 
     38   mem->memory = realloc(mem->memory, mem->size + realsize + 1);
     39   if(mem->memory == NULL) {
     40     /* out of memory! */
     41     printf("not enough memory (realloc returned NULL)\n");
     42     return 0;
     43   }
     44 
     45   memcpy(&(mem->memory[mem->size]), contents, realsize);
     46   mem->size += realsize;
     47   mem->memory[mem->size] = 0;
     48 
     49   return realsize;
     50 }
     51 
     52 int main(void)
     53 {
     54   CURL *curl;
     55   CURLcode res;
     56   struct MemoryStruct chunk;
     57   static const char *postthis="Field=1&Field=2&Field=3";
     58 
     59   chunk.memory = malloc(1);  /* will be grown as needed by realloc above */
     60   chunk.size = 0;    /* no data at this point */
     61 
     62   curl_global_init(CURL_GLOBAL_ALL);
     63   curl = curl_easy_init();
     64   if(curl) {
     65 
     66     curl_easy_setopt(curl, CURLOPT_URL, "http://www.example.org/");
     67 
     68     /* send all data to this function  */
     69     curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, WriteMemoryCallback);
     70 
     71     /* we pass our 'chunk' struct to the callback function */
     72     curl_easy_setopt(curl, CURLOPT_WRITEDATA, (void *)&chunk);
     73 
     74     /* some servers don't like requests that are made without a user-agent
     75        field, so we provide one */
     76     curl_easy_setopt(curl, CURLOPT_USERAGENT, "libcurl-agent/1.0");
     77 
     78     curl_easy_setopt(curl, CURLOPT_POSTFIELDS, postthis);
     79 
     80     /* if we don't provide POSTFIELDSIZE, libcurl will strlen() by
     81        itself */
     82     curl_easy_setopt(curl, CURLOPT_POSTFIELDSIZE, (long)strlen(postthis));
     83 
     84     /* Perform the request, res will get the return code */
     85     res = curl_easy_perform(curl);
     86     /* Check for errors */
     87     if(res != CURLE_OK) {
     88       fprintf(stderr, "curl_easy_perform() failed: %s\n",
     89               curl_easy_strerror(res));
     90     }
     91     else {
     92       /*
     93        * Now, our chunk.memory points to a memory block that is chunk.size
     94        * bytes big and contains the remote file.
     95        *
     96        * Do something nice with it!
     97        */
     98       printf("%s\n",chunk.memory);
     99     }
    100 
    101     /* always cleanup */
    102     curl_easy_cleanup(curl);
    103 
    104     free(chunk.memory);
    105 
    106     /* we're done with libcurl, so clean it up */
    107     curl_global_cleanup();
    108   }
    109   return 0;
    110 }
    111