首先基于环境的配置这里不做详细描述，请务必保证依赖所需的库文件加载进去
通过libcurl下载文件，方法实现如下：
#include <stdio.h>
#include <curl/curl.h>
#include "DownloadInfo.h"
/************************************************************************/
/* create by: mengxiaoxin date:2014/12/9 */
/************************************************************************/
/* libcurl write callback function */
size_t write_data(void *ptr, size_t size, size_t nmemb, FILE *stream) {
size_t written = fwrite(ptr, size, nmemb, stream);
return written;
}
/*
Function: libcurl connection initialization download file
Parameters: (const char* url, const char outfilename[FILENAME_MAX])
url: 要下载文件的url地址
outfilename: 下载文件指定的文件名
*/
int DOWNLOAD_FILE(const char* url, const char outfilename[FILENAME_MAX]){
CURL *curl;
FILE *fp;
CURLcode res;
/* 调用curl_global_init()初始化libcurl */
res = curl_global_init(CURL_GLOBAL_ALL);
if (CURLE_OK != res)
{
printf("init libcurl failed.");
curl_global_cleanup();
return -1;
}
/* 调用curl_easy_init()函数得到 easy interface型指针 */
curl = curl_easy_init();
if (curl) {
fopen_s(&fp,outfilename,"wb");
/* 调用curl_easy_setopt()设置传输选项 */
res = curl_easy_setopt(curl, CURLOPT_URL, url);
if (res != CURLE_OK)
{
fclose(fp);
curl_easy_cleanup(curl);
return -1;
}
/* 根据curl_easy_setopt()设置的传输选项，实现回调函数以完成用户特定任务 */
res = curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, write_data);
if (res != CURLE_OK)
{
fclose(fp);
curl_easy_cleanup(curl);
return -1;
}
/* 根据curl_easy_setopt()设置的传输选项，实现回调函数以完成用户特定任务 */
res = curl_easy_setopt(curl, CURLOPT_WRITEDATA, fp);
if (res != CURLE_OK)
{
fclose(fp);
curl_easy_cleanup(curl);
return -1;
}
res = curl_easy_perform(curl); // 调用curl_easy_perform()函数完成传输任务
fclose(fp);
/* Check for errors */
if(res != CURLE_OK){
fprintf(stderr, "curl_easy_perform() failed: %s\n",curl_easy_strerror(res));
curl_easy_cleanup(curl);
return -1;
}
/* always cleanup */
curl_easy_cleanup(curl); // 调用curl_easy_cleanup()释放内存
}
curl_global_cleanup();
return 0;
}官方的例子程序如下：
/***************************************************************************
* _ _ ____ _
* Project ___| | | | _ \| |
* / __| | | | |_) | |
* | (__| |_| | _ <| |___
* \___|\___/|_| \_\_____|
*
* Copyright (C) 1998 - 2012, 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.
*
***************************************************************************/
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <curl/curl.h>
static size_t write_data(void *ptr, size_t size, size_t nmemb, void *stream)
{
size_t written = fwrite(ptr, size, nmemb, (FILE *)stream);
return written;
}
int main(int argc, char *argv[])
{
CURL *curl_handle;
static const char *pagefilename = "page.out";
FILE *pagefile;
if(argc < 2 ) {
printf("Usage: %s <URL>\n", argv[0]);
return 1;
}
curl_global_init(CURL_GLOBAL_ALL);
/* init the curl session */
curl_handle = curl_easy_init();
/* set URL to get here */
curl_easy_setopt(curl_handle, CURLOPT_URL, argv[1]);
/* Switch on full protocol/debug output while testing */
curl_easy_setopt(curl_handle, CURLOPT_VERBOSE, 1L);
/* disable progress meter, set to 0L to enable and disable debug output */
curl_easy_setopt(curl_handle, CURLOPT_NOPROGRESS, 1L);
/* send all data to this function */
curl_easy_setopt(curl_handle, CURLOPT_WRITEFUNCTION, write_data);
/* open the file */
pagefile = fopen(pagefilename, "wb");
if (pagefile) {
/* write the page body to this file handle */
curl_easy_setopt(curl_handle, CURLOPT_WRITEDATA, pagefile);
/* get it! */
curl_easy_perform(curl_handle);
/* close the header file */
fclose(pagefile);
}
/* cleanup curl stuff */
curl_easy_cleanup(curl_handle);
return 0;
}
原文地址：http://blog.csdn.net/mxxlevel/article/details/41820351
