Retrieving response text from curl in cpp - c++

Question

we need to receive response string from curl in CPP ,I tried following options but nothing worked.js uses xhr.responseText for this.I need to do in cpp.
static size_t WriteCallback(void *contents, size_t size, size_t nmemb, void *userp)
{
size_t realsize = size * nmemb;
const char* sp = static_cast<const char*>(contents);
readBuffer.append(sp, realsize);
return realsize;
}
CURLcode res;
char* http_error= new char[100];
readBuffer.clear();
curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, WriteCallback);
curl_easy_setopt(curl, CURLOPT_WRITEDATA, &readBuffer);
CURLcode code(CURLE_FAILED_INIT);
code = curl_easy_perform(curl);
cout << "Curl response msg CURLOPT_WRITEDATA: "<<curl_easy_strerror(code)<< " respose :"<<readBuffer;
res=curl_easy_getinfo(curl, CURLINFO_RESPONSE_CODE, &http_code) ;
cout << "Curl response msg: "<< curl_easy_strerror(res);

Answer 1

Change your WriteCallback function to this:
size_t WriteCallback(void* contents, size_t size, size_t nmemb, std::string* userp) {
userp->append((char*) contents, size * nmemb);
return size * nmemb;
}
Remember, you are passing in &readBuffer as the CURL_WRITEDATA option. This shows up as the fourth parameter in the WriteCallback. Since the type of &readBuffer is std::string*, you can use that as the signature in your callback.
Additionally, since it's a std::string* and not a std::string, you have to access append through the pointer, hence the -> instead of .. After curl_easy_perform, readBuffer should hold the response from the curl request.
To get the response code, you can grab that after making the request:
long http_code;
curl_easy_getinfo(curl, CURLINFO_RESPONSE_CODE, &http_code);