#include 
     
      #include 
      
       /* For older cURL versions you will also need #include 
       
        #include 
        
         */#include 
         
          size_t write_data(void *ptr, size_t size, size_t nmemb, FILE *stream) {    size_t written = fwrite(ptr, size, nmemb, stream);    return written;}int main(void) {    CURL *curl;    FILE *fp;    CURLcode res;    char *url = "http://localhost/aaa.txt";    char outfilename[FILENAME_MAX] = "C:\\bbb.txt";    curl = curl_easy_init();    if (curl) {        fp = fopen(outfilename,"wb");        curl_easy_setopt(curl, CURLOPT_URL, url);        curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, write_data);        curl_easy_setopt(curl, CURLOPT_WRITEDATA, fp);        res = curl_easy_perform(curl);        /* always cleanup */        curl_easy_cleanup(curl);        fclose(fp);    }    return 0;}