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HIDP_BUTTON_CAPS structure (hidpi.h)

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The HIDP_BUTTON_CAPS structure contains information about the capability of a HID control button usage (or a set of buttons associated with a usage range).

Syntax

typedef struct _HIDP_BUTTON_CAPS {
  USAGE   UsagePage;
  UCHAR   ReportID;
  BOOLEAN IsAlias;
  USHORT  BitField;
  USHORT  LinkCollection;
  USAGE   LinkUsage;
  USAGE   LinkUsagePage;
  BOOLEAN IsRange;
  BOOLEAN IsStringRange;
  BOOLEAN IsDesignatorRange;
  BOOLEAN IsAbsolute;
  USHORT  ReportCount;
  USHORT  Reserved2;
  ULONG   Reserved[9];
  union {
    struct {
      USAGE  UsageMin;
      USAGE  UsageMax;
      USHORT StringMin;
      USHORT StringMax;
      USHORT DesignatorMin;
      USHORT DesignatorMax;
      USHORT DataIndexMin;
      USHORT DataIndexMax;
    } Range;
    struct {
      USAGE  Usage;
      USAGE  Reserved1;
      USHORT StringIndex;
      USHORT Reserved2;
      USHORT DesignatorIndex;
      USHORT Reserved3;
      USHORT DataIndex;
      USHORT Reserved4;
    } NotRange;
  };
} HIDP_BUTTON_CAPS, *PHIDP_BUTTON_CAPS;

Members

UsagePage

Specifies the usage page for a usage or usage range.

ReportID

Specifies the report ID of the HID report that contains the usage or usage range.

IsAlias

Indicates, if TRUE, that a button has a set of aliased usages. Otherwise, if IsAlias is FALSE, the button has only one usage.

BitField

Contains the data fields (one or two bytes) associated with an input, output, or feature main item.

LinkCollection

Specifies the index of the link collection in a top-level collection's link collection array that contains the usage or usage range. If LinkCollection is zero, the usage or usage range is contained in the top-level collection.

LinkUsage

Specifies the usage of the link collection that contains the usage or usage range. If LinkCollection is zero, LinkUsage specifies the usage of the top-level collection.

LinkUsagePage

Specifies the usage page of the link collection that contains the usage or usage range. If LinkCollection is zero, LinkUsagePage specifies the usage page of the top-level collection.

IsRange

Specifies, if TRUE, that the structure describes a usage range. Otherwise, if IsRange is FALSE, the structure describes a single usage.

IsStringRange

Specifies, if TRUE, that the usage or usage range has a set of string descriptors. Otherwise, if IsStringRange is FALSE, the usage or usage range has zero or one string descriptor.

IsDesignatorRange

Specifies, if TRUE, that the usage or usage range has a set of designators. Otherwise, if IsDesignatorRange is FALSE, the usage or usage range has zero or one designator.

IsAbsolute

Specifies, if TRUE, that the button usage or usage range provides absolute data. Otherwise, if IsAbsolute is FALSE, the button data is the change in state from the previous value.

ReportCount

HID defined report count. Available starting with API version 2.0. Call the HIDP_GetVersion function to get the API version.

Reserved2

Reserved for internal system use.

Reserved[9]

Reserved for internal system use.

Range

Specifies, if IsRange is TRUE, information about a usage range. Otherwise, if IsRange is FALSE, NotRange contains information about a single usage.

Range.UsageMin

Indicates the inclusive lower bound of usage range whose inclusive upper bound is specified by Range.UsageMax.

Range.UsageMax

Indicates the inclusive upper bound of a usage range whose inclusive lower bound is indicated by Range.UsageMin.

Range.StringMin

Indicates the inclusive lower bound of a range of string descriptors (specified by string minimum and string maximum items) whose inclusive upper bound is indicated by Range.StringMax.

Range.StringMax

Indicates the inclusive upper bound of a range of string descriptors (specified by string minimum and string maximum items) whose inclusive lower bound is indicated by Range.StringMin.

Range.DesignatorMin

Indicates the inclusive lower bound of a range of designators (specified by designator minimum and designator maximum items) whose inclusive lower bound is indicated by Range.DesignatorMax.

Range.DesignatorMax

Indicates the inclusive upper bound of a range of designators (specified by designator minimum and designator maximum items) whose inclusive lower bound is indicated by Range.DesignatorMin.

Range.DataIndexMin

Indicates the inclusive lower bound of a sequential range of data indices that correspond, one-to-one and in the same order, to the usages specified by the usage range Range.UsageMin to Range.UsageMax.

Range.DataIndexMax

Indicates the inclusive upper bound of a sequential range of data indices that correspond, one-to-one and in the same order, to the usages specified by the usage range Range.UsageMin to Range.UsageMax.

NotRange

Specifies, if IsRange is FALSE, information about a single usage. Otherwise, if IsRange is TRUE, Range contains information about a usage range.

NotRange.Usage

Indicates a usage ID.

NotRange.Reserved1

Reserved for internal system use.

NotRange.StringIndex

Indicates a string descriptor ID for the usage specified by NotRange.Usage.

NotRange.Reserved2

Reserved for internal system use.

NotRange.DesignatorIndex

Indicates a designator ID for the usage specified by NotRange.Usage.

NotRange.Reserved3

Reserved for internal system use.

NotRange.DataIndex

Indicates the data index of the usage specified by NotRange.Usage.

NotRange.Reserved4

Reserved for internal system use.

Remarks

Clients obtain a button capability array by calling HidP_GetButtonCaps or HidP_GetSpecificButtonCaps. These routines return an array of HIDP_BUTTON_CAPS structures in a caller-allocated buffer. The required buffer length is specified in the HIDP_CAPS structure returned by HidP_GetCaps.

For information about the capabilities of HID control values, see Collection Capability and Value Capability Arrays.

When a report descriptor declares an input, output, or feature main item with fewer usage declarations than the ReportCount, then the last usage applies to all remaining unspecified count in that main item. As an example, you might have data that required many fields to describe, possibly buffered bytes. In this case, only one value cap structure is allocated for these associated fields, all with the same usage, and ReportCount reflects the number of fields involved. Normally ReportCount is one. To access all of the fields in such a value structure would require using HidP_GetUsageValueArray and HidP_SetUsageValueArray. The HidP_GetUsageValue and HidP_SetScaledUsageValue functions will also work. However, these functions only work with the first field of the structure.

Requirements

Requirement Value
Header hidpi.h (include Hidpi.h)

See also