有名为GetMasterVolumeLevelScalar的成员

有名为GetMasterVolumeLevelScalar的成员

考虑以下程序:

#include <stdio.h>
#include <windows.h>
#include <mmdeviceapi.h>
#include <endpointvolume.h>
#include <math.h>
int main() {
  IAudioEndpointVolume *wh;
  IMMDevice *ya;
  IMMDeviceEnumerator *xr;
  CoInitialize(0);
  CoCreateInstance(__uuidof(MMDeviceEnumerator), 0, CLSCTX_INPROC_SERVER,
    __uuidof(IMMDeviceEnumerator), (void**)&xr);
  xr->GetDefaultAudioEndpoint(eRender, eConsole, &ya);
  ya->Activate(__uuidof(IAudioEndpointVolume), CLSCTX_ALL, 0, (void**)&wh);
  float zu;
  wh->GetMasterVolumeLevelScalar(&zu);
  printf("%d\n", (int) round(100 * zu));
}


我可以毫无问题地将其编译为C ++:

x86_64-w64-mingw32-g++ vol.cpp -lole32


但是,如果我尝试将其编译为C:

x86_64-w64-mingw32-gcc vol.c -lole32


我收到如下错误:

error: ‘IAudioEndpointVolume’ has no member named ‘GetMasterVolumeLevelScalar’


该程序似乎并不是特别的“ C ++”,是什么原因导致了
问题?另外,我可以更改某些内容以使其编译为C吗?

最佳答案

这似乎做到了:

#include <stdio.h>
#include <initguid.h>
#include <mmdeviceapi.h>
#include <endpointvolume.h>
#include <math.h>
int main() {
  IAudioEndpointVolume *wh;
  IMMDevice *ya;
  IMMDeviceEnumerator *xr;
  CoInitialize(0);
  CoCreateInstance(&CLSID_MMDeviceEnumerator, 0, CLSCTX_INPROC_SERVER,
    &IID_IMMDeviceEnumerator, (void**)&xr);
  xr->lpVtbl->GetDefaultAudioEndpoint(xr, eRender, eConsole, &ya);
  ya->lpVtbl->Activate(ya, &IID_IAudioEndpointVolume, CLSCTX_ALL,
    0, (void**)&wh);
  float zu;
  wh->lpVtbl->GetMasterVolumeLevelScalar(wh, &zu);
  printf("%d\n", (int) round(100 * zu));
}


变化:


#include <initguid.h>
&CLSID_MMDeviceEnumerator代替__uuidof(MMDeviceEnumerator)
lpVtbl->GetDefaultAudioEndpoint代替GetDefaultAudioEndpoint


Source

关于c++ - IAudioEndpointVolume没有名为GetMasterVolumeLevelScalar的成员,我们在Stack Overflow上找到一个类似的问题:https://stackoverflow.com/questions/34561252/

10-09 23:44