```c include ``` 初始化 cURL 会话： ```c CURL curl = curl_easy_init(); ``` 设置下载 URL： ```c curl_easy_setopt(curl, CURLOPT_URL, "https://example/file.txt"); ``` 4. 选择要写入的文件： ```c FILE fp = fopen("downloaded_file.txt", "wb"); curl_easy_setopt(curl, CURLOPT_WRITEDATA, fp); ``` 5. 执行下载： ```c CURLcode res = curl_easy_perform(curl); ``` 6. 检查错误： ```c if (res != CURLE_OK) { / 处理错误 / } ``` 7. 关闭 cURL 会话： ```c curl_easy_cleanup(curl); ``` 使用 fopen() 和 fread() 使用 `fopen()` 打开要下载的文件的 URL： ```c FILE fp = fopen("https://example/file.txt", "rb"); ``` 创建一个本地文件以写入下载的数据： ```c FILE local_file = fopen("downloaded_file.txt", "wb"); ``` 从 URL 读取数据并写入本地文件： ```c size_t len; char buffer[1024]; while ((len = fread(buffer, 1, sizeof(buffer), fp)) > 0) { fwrite(buffer, 1, len, local_file); } ``` 4. 关闭文件： ```c fclose(fp); fclose(local_file); ``` 其他库 [libcurl](https://curl.se/libcurl/) [libwget](https://gnu.org/software/wget/index.html) [libghttp](https://github/ghttp-org/ghttp)