Program frozen when playwave() started

I have encounter some problem when I build my .wav player using vs2013. When i load a wav it will play properly but whole program froze until the song ended. I could not even click StopButton.

void CALLBACK playSamples(HWAVEOUT hwo, UINT m, DWORD i, DWORD p1, DWORD p2)
{
    static int last = ckIn.cksize / BUFFER_SIZE;
    static int produced = 3;
    static int consumed = 1;

    if (m == WOM_DONE) {
        if (produced < last) {
            int which = produced%BUFFERS;
            if (mmioRead(hmmioIn, (databuffer[which].lpData), BUFFER_SIZE) != BUFFER_SIZE) {
                fprintf(stderr, "Error reading wave data\n");
                mmioClose(hmmioIn, 0);
                exit(-1);
            }
            waveOutWrite(hwo, &databuffer[which], sizeof(WAVEHDR));
            produced++;
        }

        if (++consumed == last) {
            finished = 1;
            return;
        }
    }
}

and

void PlayWave(char *filename)
{
    int         i, err;
    HWAVEOUT    hAudioOut;      // handle to the playback device

    readWaveFile(filename);

    // Open the audio playback device

    err = waveOutOpen(&hAudioOut, WAVE_MAPPER, (WAVEFORMATEX *)&pcmWaveFormat, (DWORD)playSamples, 0L, CALLBACK_FUNCTION);

    if (err) {

        return;
    }

    // prepare the audio buffers

    for (i = 0; i < BUFFERS; i++) {
        databuffer[i].lpData = new char[BUFFER_SIZE];
        databuffer[i].dwBufferLength = BUFFER_SIZE;
        databuffer[i].dwFlags = 0;
        memset(databuffer[i].lpData, 0, BUFFER_SIZE);
        err = waveOutPrepareHeader(hAudioOut, &databuffer[i], sizeof(WAVEHDR));

        if (err) {

            return;
        }
    }

    // fill the audio buffers

    if (mmioRead(hmmioIn, (databuffer[0].lpData), BUFFER_SIZE) != BUFFER_SIZE) {
        MessageBox::Show("Error reading wave data");
        mmioClose(hmmioIn, 0);
        return;
    }
    if (mmioRead(hmmioIn, (databuffer[1].lpData), BUFFER_SIZE) != BUFFER_SIZE) {
        fprintf(stderr, "Error reading wave data");
        mmioClose(hmmioIn, 0);
        return;
    }
    if (mmioRead(hmmioIn, (databuffer[2].lpData), BUFFER_SIZE) != BUFFER_SIZE) {
        fprintf(stderr, "Error reading wave data");
        mmioClose(hmmioIn, 0);
        return;
    }

    // Initially, play back 3 buffers of data

    waveOutWrite(hAudioOut, &databuffer[0], sizeof(WAVEHDR));
    waveOutWrite(hAudioOut, &databuffer[1], sizeof(WAVEHDR));
    waveOutWrite(hAudioOut, &databuffer[2], sizeof(WAVEHDR));

    while (!finished) { <- debug said music is being played here until end
        if (g == 0){  // g = 0 when stop button is click

            break;
        }
    }


    // close mmio handle, and close the audio device

    mmioClose(hmmioIn, 0);
    for (i = 0; i < BUFFERS; i++) {
        waveOutUnprepareHeader(hAudioOut, &databuffer[i], sizeof(WAVEHDR));
    }
    waveOutClose(hAudioOut);
    g = 1;
    return;
}

and function to trigger it

    System::Void MyForm::button1_Click(System::Object^  sender, System::EventArgs^  e) {
    array<Char>^sep = gcnew array<Char>{    ' '     };
    if (listBox1->Items->Count != 0){
        if (listBox1->SelectedIndex == -1)
            MessageBox::Show("Select a song to play");
        else{
            String^ name = listBox1->SelectedItem->ToString();
            array<String^>^result = name->Split(sep, StringSplitOptions::RemoveEmptyEntries);
            //MessageBox::Show(result[0]);
            char* pathname = (char*)(void*)Marshal::StringToHGlobalAnsi(result[0]);

            PlayWave(pathname);
        }

    }
    else
        MessageBox::Show("There are no song in the list");


}