CURLE_WRITE_ERROR

size_t write_data(void *buffer, size_t size, size_t nmemb, void *userp)
{
     
        
         
        
        return 0;
        //return size * nmemb;
}

curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, write_data);

res = curl_easy_perform(curl);

如果应答的数据大时，write_data会被多次调用，若write_date的返回值不是 size * nmemb时， curl_easy_perform(curl);会报23错误（CURLE_WRITE_ERROR）！找了我1个小时，才发现。