IOCTL_CDROM_READ_Q_CHANNEL IOCTL (ntddcdrm.h)

Returns the current position, media catalog, or ISRC track data. Reading the current position is obsolete, beginning with Windows Vista.

Major code

IRP_MJ_DEVICE_CONTROL

Input buffer

The buffer at Irp->AssociatedIrp.SystemBuffer contains a CDROM_SUB_Q_DATA_FORMAT structure with the Format member set to one of the following:

IOCTL_CDROM_CURRENT_POSITION

IOCTL_CDROM_MEDIA_CATALOG

IOCTL_CDROM_TRACK_ISRC

If Format is set to IOCTL_CDROM_TRACK_ISRC, Track must be set to the track for which ISRC data is requested.

Input buffer length

Length of a Parameters.DeviceIoControl.OutputBufferLength in the I/O stack location indicates the size, in bytes, of the buffer, which must be >= sizeof(SUB_Q_CHANNEL_DATA).

.

Output buffer

The driver returns the SUB_Q_CHANNEL_DATA information in the buffer at Irp->AssociatedIrp.SystemBuffer.

Output buffer length

Length of a SUB_Q_CHANNEL_DATA.

Status block

The Information field is set to the number of bytes returned. The Status field is set to STATUS_SUCCESS, or possibly to STATUS_BUFFER_TOO_SMALL, STATUS_IO_DEVICE_ERROR, STATUS_INSUFFICIENT_RESOURCES, STATUS_INVALID_DEVICE_REQUEST, STATUS_NO_MEDIA_IN_DEVICE, STATUS_DEVICE_NOT_READY, STATUS_IO_TIME_OUT, or STATUS_VERIFY_REQUIRED.

Remarks

Beginning with Windows Vista, CDROM class drivers do not use this IOCTL with the format member set to IOCTL_CDROM_CURRENT_POSITION. Prior to Windows Vista, this IOCTL was used for audio playback on older CD-ROM drives that supported direct audio output in hardware.

Client applications should use the Media Control Interface (MCI) API rather than issuing this IOCTL.

Requirements

See also

SUB_Q_CHANNEL_DATA