FEATURE_HEADER structure (ntddmmc.h)

The FEATURE_HEADER structure is used in conjunction with the IOCTL_CDROM_GET_CONFIGURATION request to report header information for both feature and profile descriptors.

Syntax

typedef struct _FEATURE_HEADER {
  UCHAR FeatureCode[2];
  UCHAR Current : 1;
  UCHAR Persistent : 1;
  UCHAR Version : 4;
  UCHAR Reserved0 : 2;
  UCHAR AdditionalLength;
} FEATURE_HEADER, *PFEATURE_HEADER;

Members

FeatureCode[2]

Contains a value between zero and 0xffff that indicates a feature. The FEATURE_NUMBER enumeration provides a list of currently supported feature numbers. FeatureCode[0] contains the most significant byte of the feature number. FeatureCode[1] contains the least significant byte.

Current

When set to 1, indicates that this feature is currently active and the data reported for the feature is valid. When set to zero, this bit indicates that the feature is not currently active and that the data reported for the feature might not be valid.

Persistent

Indicates, when set to 1, that the feature is always active. When set to zero, this bit indicates that the feature is not always active.

Version

Must be set to zero unless otherwise specified within the description for a particular feature.

Reserved0

Reserved.

AdditionalLength

Indicates the number of bytes of feature information that follow this header. This member must be an integral multiple of 4. The total size of the data related to this feature will be AdditionalLength + sizeof(FEATURE_HEADER).

Requirements

See also

FEATURE_NUMBER

GET_CONFIGURATION_HEADER

IOCTL_CDROM_GET_CONFIGURATION