IOCTL_CDROM_GET_PERFORMANCE IOCTL (ntddcdrm.h)
Retrieves the supported speeds from the device. The IOCTL_CDROM_GET_PERFORMANCE I/O control request is a wrapper over the MMC command, GET PERFORMANCE.
To perform this operation, call the DeviceIoControl function with IOCTL_CDROM_GET_PERFORMANCE as the dwIoControlCode parameter.
Major code
Input buffer
CDROM_PERFORMANCE_REQUEST requests performance data. CDROM_WRITE_SPEED_REQUEST requests write speed descriptor.
Input buffer length
Length of a CDROM_PERFORMANCE_REQUEST.
Output buffer
For request type CdromWriteSpeedRequest, this IOCTL returns the CDROM_PERFORMANCE_HEADER structure followed by a number of CDROM_WRITE_SPEED_DESCRIPTOR descriptors.
For request type CdromPerformanceRequest, this IOCTL returns the CDROM_PERFORMANCE_HEADER structure followed by an optional descriptor. The descriptor following this header depends on the value in the Except field of the CDROM_PERFORMANCE_HEADER structure. If Except is false, CDROM_NOMINAL_PERFORMANCE_DESCRIPTOR is used; otherwise, CDROM_EXCEPTION_PERFORMANCE_DESCRIPTOR is used.
Output buffer length
Length of a CDROM_PERFORMANCE_HEADER.
Status block
The Information field is set to the number of bytes returned.
Because of status code propagation from other APIs, the Status field can be set to (but is not limited to) the following:
STATUS_BUFFER_TOO_SMALL
The output buffer length is smaller than required.
STATUS_INFO_LENGTH_MISMATCH
The input buffer length is smaller than required.
STATUS_INVALID_DEVICE_REQUEST
The device does not support this request.
STATUS_INVALID_PARAMETER
The CDROM_PERFORMANCE_REQUEST header does not contain a valid combination of parameters specified by enumerations.
STATUS_SUCCESS
The request completed successfully.
Requirements
| Requirement | Value |
|---|---|
| Header | ntddcdrm.h (include Winioctl.h) |