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How to build a simple LED RESTful service in Raspberry PI?
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XkbAddDeviceLedInfo(3) XKB FUNCTIONS XkbAddDeviceLedInfo(3) NAME
XkbAddDeviceLedInfo - Initialize an XkbDeviceLedInfoRec structure SYNOPSIS
XkbDeviceLedInfoPtr XkbAddDeviceLedInfo (XkbDeviceInfoPtr device_info, unsigned int led_class, unsigned int led_id); ARGUMENTS
- device_info structure in which to add LED info - led_class input extension class for LED device of interest - led_id input extension ID for LED device of interest DESCRIPTION
XkbAddDeviceLedInfo first checks to see whether an entry matching led_class and led_id already exists in the device_info->leds array. If it finds a matching entry, it returns a pointer to that entry. Otherwise, it checks to be sure there is at least one empty entry in device_info->leds and extends it if there is not enough room. It then increments device_info->num_leds and fills in the next available entry in device_info->leds with led_class and led_id. If successful, XkbAddDeviceLedInfo returns a pointer to the XkbDeviceLedInfoRec structure that was initialized. If unable to allocate suf- ficient storage, or if device_info points to an invalid XkbDeviceInfoRec structure, or if led_class or led_id are inappropriate, XkbAddDe- viceLedInfo returns NULL. To allocate additional space for button actions in an XkbDeviceInfoRec structure, use XkbResizeDeviceButtonActions. STRUCTURES
Information about X Input Extension devices is transferred between a client program and the Xkb extension in an XkbDeviceInfoRec structure: typedef struct { char * name; /* name for device */ Atom type; /* name for class of devices */ unsigned short device_spec; /* device of interest */ Bool has_own_state; /* True=>this device has its own state */ unsigned short supported; /* bits indicating supported capabilities */ unsigned short unsupported; /* bits indicating unsupported capabilities */ unsigned short num_btns; /* number of entries in btn_acts */ XkbAction * btn_acts; /* button actions */ unsigned short sz_leds; /* total number of entries in LEDs vector */ unsigned short num_leds; /* number of valid entries in LEDs vector */ unsigned short dflt_kbd_fb; /* input extension ID of default (core kbd) indicator */ unsigned short dflt_led_fb; /* input extension ID of default indicator feedback */ XkbDeviceLedInfoPtr leds; /* LED descriptions */ } XkbDeviceInfoRec, *XkbDeviceInfoPtr; typedef struct { unsigned short led_class; /* class for this LED device*/ unsigned short led_id; /* ID for this LED device */ unsigned int phys_indicators; /* bits for which LEDs physically present */ unsigned int maps_present; /* bits for which LEDs have maps in maps */ unsigned int names_present; /* bits for which LEDs are in names */ unsigned int state; /* 1 bit => corresponding LED is on */ Atom names[XkbNumIndicators]; /* names for LEDs */ XkbIndicatorMapRec maps; /* indicator maps for each LED */ } XkbDeviceLedInfoRec, *XkbDeviceLedInfoPtr; SEE ALSO
XkbResizeDeviceButtonActions(3) X Version 11 libX11 1.5.0 XkbAddDeviceLedInfo(3)
