error C2065: 'CALLBACK' : undeclared identifier

[EDN Admin]

Hi! I got a code to record sound through a command line application. The code is given below. i keep receiving this error C2065: CALLBACK : undeclared identifier. Please help me solve this issue. here goes the code:

#include "stdafx.h"
#include <CommDlg.h>
#include <PrSht.h>
#include <MMSystem.h>
#include <fstream>
#include <cstdlib>
#include "resource.h"
#define NSEC 10;

using namespace std;

HWAVEIN hWaveIn;
WAVEHDR WaveInHdr;
MMRESULT result;
WAVEFORMATEX pFormat;

void CheckMMIOError(DWORD code);
void SaveWaveFile();

void main()
{

//Declare local varibles
int samplesperchan;
int sampleRate;
int *waveIn;

cout << "*********************************************n";
cout << "Configuring the Sound Hardware:n";
cout << "*********************************************n";
cout << "Enter the number of Samples/Channel:n";
cin >> samplesperchan;
cout << "Enter the Sampling Rate:n";
cin >> sampleRate;

pFormat.wFormatTag = WAVE_FORMAT_PCM; // simple, uncompressed format
pFormat.nChannels = 1; // 1=mono, 2=stereo
pFormat.nSamplesPerSec = sampleRate; // 44100
pFormat.wBitsPerSample = 16; // 16 for high quality, 8 for telephone-grade
pFormat.nBlockAlign = pFormat.nChannels*pFormat.wBitsPerSample/8;
pFormat.nAvgBytesPerSec = pFormat.nChannels*pFormat.wBitsPerSample/8;
pFormat.cbSize=0;

result = waveInOpen(&hWaveIn, WAVE_MAPPER,&pFormat,
0L, 0L, WAVE_FORMAT_DIRECT);
if (result)
{
char fault[256];
waveInGetErrorText(result, fault, 256);
MessageBoxW(NULL,L"Failed to open waveform input device.",NULL,NULL);
return;
}
int nSec = NSEC;
waveIn = new int[sampleRate*nSec];
WaveInHdr.lpData = (LPSTR)waveIn;
WaveInHdr.dwBufferLength = sampleRate*nSec*pFormat.nBlockAlign;
WaveInHdr.dwBytesRecorded=0;
WaveInHdr.dwUser = 0L;
WaveInHdr.dwFlags = 0L;
WaveInHdr.dwLoops = 0L;
waveInPrepareHeader(hWaveIn, &WaveInHdr, sizeof(WAVEHDR));

result = waveInAddBuffer(hWaveIn, &WaveInHdr, sizeof(WAVEHDR));
if (result)
{
MessageBoxW(NULL,L"Failed to read block from device",NULL,NULL);
return;
}

result = waveInStart(hWaveIn);
if (result)
{
MessageBoxW(NULL,L"Failed to start recording",NULL,NULL);
return;
}
cout << "Start Recording...........n";
do
{

}
while (waveInUnprepareHeader(hWaveIn, &WaveInHdr, sizeof(WAVEHDR))== WAVERR_STILLPLAYING);
SaveWaveFile();
waveInStop(hWaveIn);
cout << "Stop Recording.n";
waveInClose(hWaveIn);

if(!waveIn)
delete [] waveIn;
}
void SaveWaveFile()
{
MMCKINFO ChunkInfo;
MMCKINFO FormatChunkInfo;
MMCKINFO DataChunkInfo;

HMMIO handle = mmioOpen(
"test.wav", 0, MMIO_CREATE | MMIO_WRITE);
if (!handle) {
MessageBox(0, "Error creating file.", "Error Message", 0);
return;
}
memset(&ChunkInfo, 0, sizeof(MMCKINFO));
ChunkInfo.fccType = mmioStringToFOURCC("WAVE", 0);
DWORD Res = mmioCreateChunk(
handle, &ChunkInfo, MMIO_CREATERIFF);
CheckMMIOError(Res);

FormatChunkInfo.ckid = mmioStringToFOURCC("fmt ", 0);
FormatChunkInfo.cksize = sizeof(WAVEFORMATEX);
Res = mmioCreateChunk(handle, &FormatChunkInfo, 0);
CheckMMIOError(Res);
// Write the wave format data.
mmioWrite(handle, (char*)&pFormat, sizeof(pFormat));

Res = mmioAscend(handle, &FormatChunkInfo, 0);
CheckMMIOError(Res);
DataChunkInfo.ckid = mmioStringToFOURCC("data", 0);
DWORD DataSize = WaveInHdr.dwBytesRecorded;
DataChunkInfo.cksize = DataSize;
Res = mmioCreateChunk(handle, &DataChunkInfo, 0);
CheckMMIOError(Res);

mmioWrite(handle, (char*)WaveInHdr.lpData, DataSize);
// Ascend out of the data chunk.
mmioAscend(handle, &DataChunkInfo, 0);

// Ascend out of the RIFF chunk (the main chunk). Failure to do
// this will result in a file that is unreadable by Windows95
// Sound Recorder.
mmioAscend(handle, &ChunkInfo, 0);
mmioClose(handle, 0);
}
void CheckMMIOError(DWORD code)
{
if (code == 0) return;
char buff[256];
wsprintf(buff,
"MMIO Error. Error Code: %d", code);
MessageBox(NULL,buff, "MMIO Error", 0);
}



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