This message requests an ACM driver to return hardware capabilities for a waveform input device.
MMSYSERR_NOERROR indicates success. Otherwise the driver returns one of the MMSYSERR error values declared in the Mmsystem.h header file or one of the ACMERR error values declared in the Msacm.h header file. If the driver does not support waveform hardware, it returns MMSYSERR_NOTSUPPORTED.
Each time a client calls the acmMetrics function with the ACM_METRIC_HARDWARE_WAVE_INPUT index parameter, the ACM (Waveapi.dll) sends this message by calling the ACM driver’s ACM_IOControl entry point through the DeviceIoControl function..
The driver receives a pointer to a WAVEINCAPS structure. The driver must fill in the structure.
Only ACM drivers that provide access to waveform input hardware need to support this message. If your driver supports this message, it must return ACMDRIVERDETAILS_SUPPORTF_HARDWARE in the ACMDRIVERDETAILS structure provided with the ACMDM_DRIVER_DETAILS message. For more information about providing ACM support, see the Windows NT DDK.