如何正确重复使用卷曲手柄

我想正确地重用卷曲句柄，这样它就不会给我错误并正常运行。

假设我有这段代码：

    CURL *curl;

    curl_global_init(CURL_GLOBAL_ALL);
    curl = curl_easy_init();

    curl_easy_setopt(curl, CURLOPT_USERAGENT, "Mozilla/5.0...");
    curl_easy_setopt(curl, CURLOPT_URL, "http://www.google.com");
    curl_easy_perform(curl);

    curl_easy_setopt(curl, CURLOPT_URL, "http://www.bbc.com");
    curl_easy_perform(curl);

    curl_easy_cleanup(curl);
    curl_global_cleanup();

这是重复使用卷曲手柄的好方法还是正确方法？或者我需要使用curl_easy_reset()在那个手柄上？

如果有人建议你在curl中应该避免做什么，我也将不胜感激。也许有人可以给我一个现有信息源的链接？

如果我正确理解了这个问题，您想知道是否可以致电curl_easy_perform() https://curl.haxx.se/libcurl/c/curl_easy_perform.html然后只通过更改urlcurl_easy_setopt() https://curl.haxx.se/libcurl/c/curl_easy_setopt.html然后再打第二个电话？这应该不会出现任何错误，因为该函数不会更改句柄的任何先前设置的选项。这是一个简短的工作示例：

size_t writeCallback(char* contents, size_t size, size_t nmemb, std::string* buffer) {
  size_t realsize = size * nmemb;
  if(buffer == NULL) {
    return 0;
  }
  buffer->append(contents, realsize);
  return realsize;  
}

int main(int argc, char** argv) {
  std::string buffer;

  // Initialize global.
  curl_global_init(CURL_GLOBAL_ALL);

  // Start a libcurl easy session.
  CURL* ch = curl_easy_init();
  if (!ch) {
    // Something went wrong
    curl_global_cleanup();
    return -1;
  }

  // These options will only be set once.
  curl_easy_setopt(ch, CURLOPT_VERBOSE, 0);
  curl_easy_setopt(ch, CURLOPT_FOLLOWLOCATION, 1);
  curl_easy_setopt(ch, CURLOPT_USERAGENT, "Crawler");
  curl_easy_setopt(ch, CURLOPT_WRITEFUNCTION, &writeCallback);
  curl_easy_setopt(ch, CURLOPT_WRITEDATA, &buffer);

  // Push a couple of URLs onto queue.
  std::vector<const char*> queue;
  queue.push_back("http://www.google.com");
  queue.push_back("http://www.stackoverflow.com");

  const char* url;
  CURLcode code;

  do {
      // Grab an URL from the queue.
      url = queue.back();
      queue.pop_back();

      // Only change the CURLOPT_URL option for the handle
      // the rest will stay intact.
      curl_easy_setopt(ch, CURLOPT_URL, url);

      // Perform transfer.
      code = curl_easy_perform(ch);

      // Check if everything went fine.
      if (code != CURLE_OK) {
        // Handle any errors.
      }

      // Clear the buffer.
      buffer.clear();
  } while (queue.size() > 0);

  // Cleanup.
  curl_easy_cleanup(ch);
  curl_global_cleanup();

  return 0;
}

或者我是否需要在该句柄上使用curl_easy_reset()？

答案是no since curl_easy_perform() https://curl.haxx.se/libcurl/c/curl_easy_perform.html不会重置任何选项，您的代码应该没问题，您可以坚持只更改网址，例如curl_easy_setoption(curl, CURLOPT_URL, <newurl>);.