Web pages extraction & Libcurl

Good morning.

I've tried to extract, using libcurl, web pages but it failed. There
is no compilation error concerning the class I wrote, but the problems
appear when I compile a main method which calls this class.

My class :

**********************************libcurl_tools.h

#include <curl/curl.h>

struct MemoryStruct {
    char *memory;
    size_t size;
};

class libcurl_tools {

    CURL * curl_handle;
    MemoryStruct chunk;

    public:

    libcurl_tools();
    void init();
    bool close();
    void set_referrer(std::string, CURL *);
    std::string perform(std::string, CURL *);

};

**********************************libcurl_tools.cpp

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include <curl/curl.h>
#include <curl/types.h>
#include <curl/easy.h>

#include <iostream> // pour std::cout
#include <string> // pour std::string

#include "libcurl_tools.h"

libcurl_tools::libcurl_tools() {}

static void *myrealloc(void *ptr, size_t size)
{
    /* There might be a realloc() out there that doesn't like reallocing
       NULL pointers, so we take care of it here */
    if(ptr)
        return realloc(ptr, size);
    else
        return malloc(size);
}

static size_t WriteMemoryCallback(void *ptr, size_t size, size_t
nmemb, void *data)
{
    size_t realsize = size * nmemb;
    struct MemoryStruct *mem = (struct MemoryStruct *)data;

    mem->memory = (char *)myrealloc(mem->memory, mem->size + realsize +
1);
    if (mem->memory) {
        memcpy(&(mem->memory[mem->size]), ptr, realsize);
        mem->size += realsize;
        mem->memory[mem->size] = 0;
    }
    return realsize;
}

void libcurl_tools::set_referrer(std::string referer, CURL
*curl_handle ) {

    curl_easy_setopt(curl_handle, CURLOPT_REFERER, referer.c_str());

}

//initialise la connection
void libcurl_tools::init() {

    chunk.memory=NULL; /* we expect realloc(NULL, size) to work */
    chunk.size = 0; /* no data at this point */

    curl_global_init(CURL_GLOBAL_ALL);

    /* init the curl session */
    curl_handle = curl_easy_init();

}

//t=E9l=E9charge l'url en argument
std::string libcurl_tools::perform(std::string url , CURL
*curl_handle) {

    /* specify URL to get */
    curl_easy_setopt(curl_handle, CURLOPT_URL, url.c_str());

    /* send all data to this function */
    curl_easy_setopt(curl_handle, CURLOPT_WRITEFUNCTION,
WriteMemoryCallback);

    /* we pass our 'chunk' struct to the callback function */
    curl_easy_setopt(curl_handle, CURLOPT_WRITEDATA, (void *)&chunk);

    /* some servers don't like requests that are made without a user-
agent
       field, so we provide one */
    curl_easy_setopt(curl_handle, CURLOPT_USERAGENT, "libcurl-agent/
1.0");

    /* get it! */
    curl_easy_perform(curl_handle);

    /* cleanup curl stuff */
    curl_easy_cleanup(curl_handle);

    /*
     * Now, our chunk.memory points to a memory block that is chunk.size
     * bytes big and contains the remote file.
     *
     * Do something nice with it!
     *
     * You should be aware of the fact that at this point we might have
an
     * allocated data block, and nothing has yet deallocated that data.
So when
     * you're done with it, you should free() it as a nice application.
     */

    //return chunk.memory; // les 2 ont l'air de marcher (pour le
moment...)
    return std::string(chunk.memory);

}

bool libcurl_tools::close() {

    if(chunk.memory)
        free(chunk.memory);

    return 0;
}

*********************************** test.cpp which includes the main()

#include <iostream>
#include <string>
#include <sstream>
#include "libcurl_tools.h"

//#include <stdio.h>

using namespace std;

int main()
{

 libcurl_tools e();

    e.init();

    std::string chaine;
    std:: string s = "www.yahoo.com";

 chaine = e.perform(s);

   e.close();

}

There are 3 compilation errors concerning the calls of init(),
perform() and close() methods, and I really don't know why it happens.
I wish you could help me guys...

Thanks