Google Speech API with libcurl

// Aralox - http://stackoverflow.com/questions/25307487/how-to-use-libcurl-with-google-speech-api-what-is-the-equivalent-for-data-bin/25310710#25310710

#include <iostream>
#include <stdio.h>
#include <curl/curl.h>
#include <direct.h>
#include <string>

struct WriteThis {
    const char *readptr;
    long sizeleft;
};

// callback function from http://curl.haxx.se/libcurl/c/post-callback.html
static size_t read_callback(void *ptr, size_t size, size_t nmemb, void *userp)
{
    struct WriteThis *pooh = (struct WriteThis *)userp;

    if (size*nmemb < 1)
        return 0;

    if (pooh->sizeleft) {
        *(char *)ptr = pooh->readptr[0]; /* copy one single byte */
        pooh->readptr++;                 /* advance pointer */
        pooh->sizeleft--;                /* less data left */
        return 1;                        /* we return 1 byte at a time! */
    }

    return 0;                          /* no more data left to deliver */
}

int main(void)
{
    CURL *curl;         // curl handle
    CURLcode res;

    curl = curl_easy_init();
    if (curl)
    {
        FILE *file;
        errno_t err = fopen_s(&file, "testaudio.wav", "r");
        fseek(file, 0, SEEK_END);
        int fileSize = ftell(file);
        fseek(file, 0, SEEK_SET);

        std::cout << "file open status: " << err << std::endl;
        std::cout << "file " << fileSize << std::endl;

        struct curl_slist *chunk = NULL;
        chunk = curl_slist_append(chunk, "Content-Type: audio/l16; rate=44100");

        char *audioData = (char*)malloc(fileSize);
        struct WriteThis pooh;
        fread(audioData, fileSize, 1, file);
        fclose(file);

        pooh.readptr = audioData;
        pooh.sizeleft = fileSize;

        std::string sizeHeader = "Content-Length: ";
        sizeHeader += std::to_string(fileSize);
        chunk = curl_slist_append(chunk, sizeHeader.c_str());

        std::cout << curl_easy_setopt(curl, CURLOPT_POST, 1L) << std::endl;
        curl_easy_setopt(curl, CURLOPT_READFUNCTION, read_callback);
        curl_easy_setopt(curl, CURLOPT_READDATA, &pooh);
        curl_easy_setopt(curl, CURLOPT_VERBOSE, 1L);

        std::cout << curl_easy_setopt(curl, CURLOPT_HTTPHEADER, chunk) << std::endl;
        std::cout << curl_easy_setopt(curl, CURLOPT_CAINFO, "ca-bundle.crt") << std::endl;
        std::cout << curl_easy_setopt(curl, CURLOPT_URL, "https://www.google.com/speech-api/v2/recognize?output=json&lang=en-us&key=yourkey") << std::endl;

        res = curl_easy_perform(curl);
        std::cout << res;
        curl_easy_cleanup(curl);

    }
    return 0;
}