- XArc
- Xau library: XauFileName
- XAutoRepeatOff
- XAutoRepeatOn
- XBaseFontNameListOfFontSet
- XBell
- XButtonEvent
- XChangeActivePointerGrab
- XChangeDeviceControl
- XChangeDeviceDontPropagateList
- XChangeDeviceKeyMapping
- XChangeFeedbackControl
- XChangeGC
- XChangeKeyboardControl
- XChangeKeyboardDevice
- XChangeKeyboardMapping
- XChangePointerControl
- XChangePointerDevice
- XChangeSaveSet
- XChangeWindowAttributes
- XChar2b
- XCharStruct
- XCheckIfEvent
- XCheckMaskEvent
- XCheckTypedEvent
- XCheckTypedWindowEvent
- XCheckWindowEvent
- XCirculateEvent
- XCirculateRequestEvent
- XCirculateSubwindows
- XCirculateSubwindowsDown
- XCirculateSubwindowsUp
- XClassHint
- XClearArea
- XClearWindow
- XClientMessageEvent
- XCloseDevice
- XCloseDisplay
- XCloseIM
- XCloseOM
- XcmsAllocColor
- XcmsAllocNamedColor
- XcmsCCCOfColormap
- XcmsCIELab
- XcmsCIELabQueryMaxC
- XcmsCIELabQueryMaxL
- XcmsCIELabQueryMaxLC
- XcmsCIELabQueryMinL
- XcmsCIELuv
- XcmsCIELuvQueryMaxC
- XcmsCIELuvQueryMaxL
- XcmsCIELuvQueryMaxLC
- XcmsCIELuvQueryMinL
- XcmsCIEuvY
- XcmsCIExyY
- XcmsCIEXYZ
- XcmsColor
- XcmsConvertColors
- XcmsCreateCCC
- XcmsDefaultCCC
- XcmsFreeCCC
- XcmsLookupColor
- XcmsPad
- XcmsQueryBlack
- XcmsQueryBlue
- XcmsQueryColor
- XcmsQueryColors
- XcmsQueryGreen
- XcmsQueryRed
- XcmsQueryWhite
MAN (3)
Library functions, covering in particular the C standard library