HIDP_BUTTON_CAPS structure (hidpi.h)
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) |