libcurl读取网页数据到内存中

#include <stdlib.h>
#include <stdio.h>
#include <curl/curl.h>
#include <curl/easy.h>
#include <string>
#include <iostream>
using namespace std;
static char errorBuffer[1024];

static void startChoice() {
    string                     buffer;
    CURLcode                   code;
    CURL*                      curl = NULL;
    const char* url = "www.baidu.com";
    code = curl_global_init(CURL_GLOBAL_DEFAULT);
    printf("code = %d\n", code);
    curl = curl_easy_init();
    if(!init(curl, url, &buffer))
    {
        fprintf(stderr, "Connection initializion failed\n");
        exit(EXIT_FAILURE);
        
    }
    code = curl_easy_perform(curl);
    if (code != CURLE_OK)
    {
        fprintf(stderr, "Failed to get '%s' [%s]\n", url, errorBuffer);
        exit(EXIT_FAILURE);
        
    }
    curl_easy_cleanup(curl);
    printf("%s\n",buffer.c_str());
}

static bool init(CURL *&curl, const char *url, string *p_buffer)
{
    CURLcode code;
    curl = curl_easy_init();
    if (curl == NULL)
    {
        fprintf(stderr, "Failed to create CURL connection\n");
        exit(EXIT_FAILURE);
    }
    code = curl_easy_setopt(curl, CURLOPT_ERRORBUFFER, errorBuffer);
    if (code != CURLE_OK)
    {
        fprintf(stderr, "Failed to set error buffer [%d]\n", code);
        return false;
    }
    code = curl_easy_setopt(curl, CURLOPT_URL, url);
    if (code != CURLE_OK)
    {
        fprintf(stderr, "Failed to set URL [%s]\n", errorBuffer);
        return false;
    }
    code = curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, writer);
    if (code != CURLE_OK)
    {
        fprintf(stderr, "Failed to set writer [%s]\n", errorBuffer);
        return false;
    }
    code = curl_easy_setopt(curl, CURLOPT_WRITEDATA, p_buffer);
    if (code != CURLE_OK)
    {
        fprintf(stderr, "Failed to set write data [%s]\n", errorBuffer);
        return false;
    }
    return true;
}

static int writer(char *data, size_t size, size_t nmemb, string *writerData)
{
    unsigned long sizes = size * nmemb;
    if (writerData == NULL) return 0;
    writerData->append(data, sizes);
    return sizes;
}