关于WaveOutOpen等函数的用法，举个例子(200分)

不用控件，对声卡进行操作

#include
#include
#include "resource.h"

#define SAMPLE_RATE 11025
#define FREQ_MIN 20
#define FREQ_MAX 5000
#define FREQ_INIT 440
#define OUT_BUFFER_SIZE 4096
#define PI 3.14159

BOOL CALLBACK DlgProc (HWND, UINT, WPARAM, LPARAM)

TCHAR szAppName [] = TEXT ("SineWave")

int WINAPI WinMain (HINSTANCE hInstance, HINSTANCE hPrevInstance,
PSTR szCmdLine, int iCmdShow)
{
if (-1 == DialogBox (hInstance, szAppName, NULL, DlgProc))
{
MessageBox (NULL, TEXT ("This program requires Windows NT!"),
szAppName, MB_ICONERROR)
}
return 0
}

VOID FillBuffer (PBYTE pBuffer, int iFreq)
{
staticdo
uble fAngle
int i

for (i = 0
i < OUT_BUFFER_SIZE
i++)
{
pBuffer = (BYTE) (127 + 127 * sin (fAngle))

fAngle += 2 * PI * iFreq / SAMPLE_RATE

if (fAngle > 2 * PI)
fAngle -= 2 * PI
}
}

BOOL CALLBACK DlgProc (HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
{
static BOOL bShutOff, bClosing
static HWAVEOUT hWaveOut
static HWND hwndScroll
static int iFreq = FREQ_INIT
static PBYTE pBuffer1, pBuffer2
static PWAVEHDR pWaveHdr1, pWaveHdr2
static WAVEFORMATEX waveformat
int iDummy

switch (message)
{
case WM_INITDIALOG:
hwndScroll = GetDlgItem (hwnd, IDC_SCROLL)
SetScrollRange (hwndScroll, SB_CTL, FREQ_MIN, FREQ_MAX, FALSE)
SetScrollPos (hwndScroll, SB_CTL, FREQ_INIT, TRUE)
SetDlgItemInt (hwnd, IDC_TEXT, FREQ_INIT, FALSE)

return TRUE

case WM_HSCROLL:
switch (LOWORD (wParam))
{
case SB_LINELEFT: iFreq -= 1
break
case SB_LINERIGHT: iFreq += 1
break
case SB_PAGELEFT: iFreq /= 2
break
case SB_PAGERIGHT: iFreq *= 2
break

case SB_THUMBTRACK:
iFreq = HIWORD (wParam)
break

case SB_TOP:
GetScrollRange (hwndScroll, SB_CTL, &amp;
ifreq, &amp;iDummy)
break

case SB_BOTTOM:
GetScrollRange (hwndScroll, SB_CTL, &amp;iDummy, &amp;
ifreq)
break
}

iFreq = max (FREQ_MIN, min (FREQ_MAX, iFreq))

SetScrollPos (hwndScroll, SB_CTL, iFreq, TRUE)
SetDlgItemInt (hwnd, IDC_TEXT, iFreq, FALSE)
return TRUE

case WM_COMMAND:
switch (LOWORD (wParam))
{
case IDC_ONOFF:
// If turning on waveform, hWaveOut is NULL

if (hWaveOut == NULL)
{
// Allocate memory for 2 headers and 2 buffers

pWaveHdr1 = malloc (sizeof (WAVEHDR))
pWaveHdr2 = malloc (sizeof (WAVEHDR))
pBuffer1 = malloc (OUT_BUFFER_SIZE)
pBuffer2 = malloc (OUT_BUFFER_SIZE)

if (!pWaveHdr1 || !pWaveHdr2 || !pBuffer1 || !pBuffer2)
{
if (!pWaveHdr1) free (pWaveHdr1)
if (!pWaveHdr2) free (pWaveHdr2)
if (!pBuffer1) free (pBuffer1)
if (!pBuffer2) free (pBuffer2)

MessageBeep (MB_ICONEXCLAMATION)
MessageBox (hwnd, TEXT ("Error allocating memory!"),
szAppName, MB_ICONEXCLAMATION | MB_OK)
return TRUE
}

// Variable to indicate Off button pressed

bShutOff = FALSE

// Open waveform audio for output

waveformat.wFormatTag = WAVE_FORMAT_PCM
waveformat.nChannels = 1
waveformat.nSamplesPerSec = SAMPLE_RATE
waveformat.nAvgBytesPerSec = SAMPLE_RATE
waveformat.nBlockAlign = 1
waveformat.wBitsPerSample = 8
waveformat.cbSize = 0

if (waveOutOpen (&amp;hWaveOut, WAVE_MAPPER, &amp;waveformat,
(DWORD) hwnd, 0, CALLBACK_WINDOW)
!= MMSYSERR_NOERROR)
{
free (pWaveHdr1)
free (pWaveHdr2)
free (pBuffer1)
free (pBuffer2)

hWaveOut = NULL
MessageBeep (MB_ICONEXCLAMATION)
MessageBox (hwnd,
TEXT ("Error opening waveform audio device!"),
szAppName, MB_ICONEXCLAMATION | MB_OK)
return TRUE
}

// Set up headers and prepare them

pWaveHdr1->lpData = pBuffer1
pWaveHdr1->dwBufferLength = OUT_BUFFER_SIZE
pWaveHdr1->dwBytesRecorded = 0
pWaveHdr1->dwUser = 0
pWaveHdr1->dwFlags = 0
pWaveHdr1->dwLoops = 1
pWaveHdr1->lpNext = NULL
pWaveHdr1->reserved = 0

waveOutPrepareHeader (hWaveOut, pWaveHdr1,
sizeof (WAVEHDR))

pWaveHdr2->lpData = pBuffer2
pWaveHdr2->dwBufferLength = OUT_BUFFER_SIZE
pWaveHdr2->dwBytesRecorded = 0
pWaveHdr2->dwUser = 0
pWaveHdr2->dwFlags = 0
pWaveHdr2->dwLoops = 1
pWaveHdr2->lpNext = NULL
pWaveHdr2->reserved = 0

waveOutPrepareHeader (hWaveOut, pWaveHdr2,
sizeof (WAVEHDR))
}
// If turning off waveform, reset waveform audio
else

{
bShutOff = TRUE
waveOutReset (hWaveOut)
}
return TRUE
}
break

// Message generated from waveOutOpen call

case MM_WOM_OPEN:
SetDlgItemText (hwnd, IDC_ONOFF, TEXT ("Turn Off"))

// Send two buffers to waveform output device

FillBuffer (pBuffer1, iFreq)
waveOutWrite (hWaveOut, pWaveHdr1, sizeof (WAVEHDR))

FillBuffer (pBuffer2, iFreq)
waveOutWrite (hWaveOut, pWaveHdr2, sizeof (WAVEHDR))
return TRUE

// Message generated when a buffer is finished

case MM_WOM_DONE:
if (bShutOff)
{
waveOutClose (hWaveOut)
return TRUE
}

// Fill and send out a new buffer

FillBuffer (((PWAVEHDR) lParam)->lpData, iFreq)
waveOutWrite (hWaveOut, (PWAVEHDR) lParam, sizeof (WAVEHDR))
return TRUE

case MM_WOM_CLOSE:
waveOutUnprepareHeader (hWaveOut, pWaveHdr1, sizeof (WAVEHDR))
waveOutUnprepareHeader (hWaveOut, pWaveHdr2, sizeof (WAVEHDR))

free (pWaveHdr1)
free (pWaveHdr2)
free (pBuffer1)
free (pBuffer2)

hWaveOut = NULL
SetDlgItemText (hwnd, IDC_ONOFF, TEXT ("Turn On"))

if (bClosing)
EndDialog (hwnd, 0)

return TRUE

case WM_SYSCOMMAND:
switch (wParam)
{
case SC_CLOSE:
if (hWaveOut != NULL)
{
bShutOff = TRUE
bClosing = TRUE

waveOutReset (hWaveOut)
}
else

EndDialog (hwnd, 0)

return TRUE
}
break
}
return FALSE
}

从MSDN查来的，是个VB的程序，但API函数的是用上应该差不多的。
http://support.microsoft.com/download/support/mslfiles/LLStream.exe

The sample uses several low-level functions in the Windows API to work around the Multimedia Control Interface. You must be familiar with using Visual Basic to call the Windows API functions to understand how this sample works.
When you run the self-extracting executable file, the following files are expanded into the Low-Level Streaming Audio Sample Project directory:

Form1.frm (3Kb) - the main form
Module1.bas (12Kb) - the module containing the function declarations
Project1.vbp (1Kb) - the main project file
Project1.vbw (1Kb) - the project workspace
Readme.txt - overview of the sample anddo
wnload information

继续

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