problem with waveinopen under Vista

Giovanni Maruzzelli gmaruzz.lists@gmail.com
Mon Mar 10 12:48:00 GMT 2008


Hi Cygwin developers,

I got a problem using waveInOpen under Vista:

1) As soon as waveInOpen is called, the cpu load becomes very high,
80% on a quad core.
2) To cause the high load it is not needed to use the wavein, just to open it.
3) Under XP, no problems.
4) If you compile under vista with -mno-cygwin and execute with a
double click on it, no problem.
5) If you compile using cygwin, and execute it from bash, 80% load.

See below a very simple test case.

You can compile it without cygwin and then execute it with a double click:
gcc -mno-cygwin -Wall waveinopen_vista.c -o waveinopen_vista -l winmm

or you can compile it with cygwin and execute it from bash:
gcc -Wall waveinopen_vista.c -o waveinopen_vista -l winmm

=======================================
#include <windows.h>
#include <stdio.h>
#include <mmsystem.h>


/* Handle to the WAVE In Device */
HWAVEIN                         WaveInHandle;

int main(int argc , char ** argv)
{
MMRESULT        err;
WAVEFORMATEX    waveFormat;

/* Initialize the WAVEFORMATEX */
waveFormat.wFormatTag = WAVE_FORMAT_PCM;
waveFormat.nChannels = 2;
waveFormat.nSamplesPerSec = 44100;
waveFormat.wBitsPerSample = 16;
waveFormat.nBlockAlign = waveFormat.nChannels *
       (waveFormat.wBitsPerSample/8);
waveFormat.nAvgBytesPerSec = waveFormat.nSamplesPerSec *
       waveFormat.nBlockAlign;
waveFormat.cbSize = 0;


/* Open the default WAVE In Device */

/* if you open it with or without a callback thread,
  the cpu load is the same */
//err = waveInOpen(&WaveInHandle, WAVE_MAPPER, &waveFormat,
//              (DWORD)err, 0, CALLBACK_THREAD);
err = waveInOpen(&WaveInHandle, WAVE_MAPPER, &waveFormat,
               0, 0, CALLBACK_NULL);

printf("\n\nciao!!!\n\n");
Sleep(500000000);
printf("\n\ngoodbye!!!\n\n");

return 0;
}

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