C++ 从libcurl中的内存上载图像

是否可以将图像从FTP客户端的内存发送到FTP服务器，而不是在C++libcurl中发送文件？当然，图像最终应该作为文件保存在FTP服务器上

目前，我正在使用以下示例：。我先将图片存储到一个文件中，然后上传，但这对我的应用程序来说太慢了

我需要的是给curl我记忆中图像的地址。有人有这方面的经验吗

代码如下：

static size_t read_callback(void *ptr, size_t size, size_t nmemb, void *stream)
{
  curl_off_t nread;
  /* in real-world cases, this would probably get this data differently
     as this fread() stuff is exactly what the library already would do
     by default internally */ 
  size_t retcode = fread(ptr, size, nmemb, stream);

  nread = (curl_off_t)retcode;

  fprintf(stderr, "*** We read %" CURL_FORMAT_CURL_OFF_T
          " bytes from file\n", nread);
  return retcode;
}

int main(void)
{
  CURL *curl;
  CURLcode res;
  FILE *hd_src;
  struct stat file_info;
  curl_off_t fsize;

  struct curl_slist *headerlist=NULL;
  static const char buf_1 [] = "RNFR " UPLOAD_FILE_AS;
  static const char buf_2 [] = "RNTO " RENAME_FILE_TO;

  /* get the file size of the local file */ 
  if(stat(LOCAL_FILE, &file_info)) {
    printf("Couldnt open '%s': %s\n", LOCAL_FILE, strerror(errno));
    return 1;
  }
  fsize = (curl_off_t)file_info.st_size;

  printf("Local file size: %" CURL_FORMAT_CURL_OFF_T " bytes.\n", fsize);

  /* get a FILE * of the same file */ 
  hd_src = fopen(LOCAL_FILE, "rb");

  /* In windows, this will init the winsock stuff */ 
  curl_global_init(CURL_GLOBAL_ALL);

  /* get a curl handle */ 
  curl = curl_easy_init();
  if(curl) {
    /* build a list of commands to pass to libcurl */ 
    headerlist = curl_slist_append(headerlist, buf_1);
    headerlist = curl_slist_append(headerlist, buf_2);

    /* we want to use our own read function */ 
    curl_easy_setopt(curl, CURLOPT_READFUNCTION, read_callback);

    /* enable uploading */ 
    curl_easy_setopt(curl, CURLOPT_UPLOAD, 1L);

    /* specify target */ 
    curl_easy_setopt(curl, CURLOPT_URL, REMOTE_URL);

    /* pass in that last of FTP commands to run after the transfer */ 
    curl_easy_setopt(curl, CURLOPT_POSTQUOTE, headerlist);

    /* now specify which file to upload */ 
    curl_easy_setopt(curl, CURLOPT_READDATA, hd_src);

    /* Set the size of the file to upload (optional).  If you give a *_LARGE
       option you MUST make sure that the type of the passed-in argument is a
       curl_off_t. If you use CURLOPT_INFILESIZE (without _LARGE) you must
       make sure that to pass in a type 'long' argument. */ 
    curl_easy_setopt(curl, CURLOPT_INFILESIZE_LARGE,
                     (curl_off_t)fsize);

    /* Now run off and do what you've been told! */ 
    res = curl_easy_perform(curl);
    /* Check for errors */ 
    if(res != CURLE_OK)
      fprintf(stderr, "curl_easy_perform() failed: %s\n",
              curl_easy_strerror(res));

    /* clean up the FTP commands list */ 
    curl_slist_free_all(headerlist);

    /* always cleanup */ 
    curl_easy_cleanup(curl);
  }
  fclose(hd_src); /* close the local file */ 

  curl_global_cleanup();
  return 0;
}

---

查看中的代码，了解如何执行此操作

只需从

read\u回调中的内存缓冲区读取

我刚刚制作了一个正式的libcurl示例，展示了