Creating a dll using libcurl in c++ with MinGW - c++

Question

**How to make a dll using libcurl. can you share me a sample code.**
#include <math.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <iostream>
#include <curl/curl.h>
using namespace std; string data; typedef
#ifdef BUILDING_TESTCURL_DLL
#define TESTCURL_DLL __declspec(dllexport)
#else
#define TESTCURL_DLL __declspec(dllimport)
#endif
curl_global_init(CURL_GLOBAL_ALL); //pretty obvious
curl = curl_easy_init();
curl_easy_setopt(curl, CURLOPT_URL, lpURL);
curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, &writeCallback);
curl_easy_setopt(curl, CURLOPT_WRITEDATA, &response);
curl_easy_perform(curl);
if (data == "1")
{
//printf("Successfull");
strcpy(Result, "1");
}
v5 = 1;
curl_easy_cleanup(curl);
curl_global_cleanup();
size_t TESTCURL_DLL writeCallback(char* buf, size_t size, size_t
nmemb, void* up) {
for (int c = 0; c<size*nmemb; c++) { data.push_back(buf[c]);
//printf("", buf[c]); } return size*nmemb; //tell curl how many
bytes we handled }
I run this code with MinGW: g++ -shared -o testcurl.dll testcurl.o -Wl,--out-implib,libcurldll.a
it shows error: undefined reference to '_imp_curl_easy_setopt' undefined reference to '_imp_curl_easy_perform' undefined reference to '_imp_curl_easy_init'
Please help me for developing a dll file using curl.