AllPlanes, BlackPixel, WhitePixel, ConnectionNumber,
DefaultColormap, DefaultDepth, XListDepths, DefaultGC,
DefaultRootWindow, DefaultScreenOfDisplay, DefaultScreen,
DefaultVisual, DisplayCells, DisplayPlanes, DisplayString,
XMaxRequestSize, XExtendedMaxRequestSize,
LastKnownRequestProcessed, NextRequest, ProtocolVersion,
ProtocolRevision, QLength, RootWindow, ScreenCount,
ScreenOfDisplay, ServerVendor, VendorRelease − Display
macros and functions

unsigned long AllPlanes; unsigned long BlackPixel(Display
*display, int screen_number); unsigned long
WhitePixel(Display *display, int screen_number); int
ConnectionNumber(Display *display); Colormap
DefaultColormap(Display *display, int screen_number); int
DefaultDepth(Display *display, int screen_number); int
*XListDepths(Display *display, int screen_number, int
*count_return); GC DefaultGC(Display *display, int
screen_number); Window DefaultRootWindow(Display *display);
Screen *DefaultScreenOfDisplay(Display *display); int
DefaultScreen(Display *display); Visual
*DefaultVisual(Display *display, int screen_number); int
DisplayCells(Display *display, int screen_number); int
DisplayPlanes(Display *display, int screen_number); char
*DisplayString(Display *display); long
XMaxRequestSize(Display *display); long
XExtendedMaxRequestSize(Display *display); unsigned long
LastKnownRequestProcessed(Display *display); unsigned long
NextRequest(Display *display); int ProtocolVersion(Display
*display); int ProtocolRevision(Display *display); int
QLength(Display *display); Window RootWindow(Display
*display, int screen_number); int ScreenCount(Display
*display); Screen *ScreenOfDisplay(Display *display, int
screen_number); char *ServerVendor(Display *display); int
VendorRelease(Display *display);

display   Specifies the connection to the X server.

          Specifies the appropriate screen number on the
          host server.

          Returns the number of depths.

The AllPlanes macro returns a value with all bits set to 1
suitable for use in a plane argument to a procedure.

The BlackPixel macro returns the black pixel value for the
specified screen.


The WhitePixel macro returns the white pixel value for the
specified screen.

The ConnectionNumber macro returns a connection number for
the specified display.

The DefaultColormap macro returns the default colormap ID
for allocation on the specified screen.

The DefaultDepth macro returns the depth (number of planes)
of the default root window for the specified screen.

The XListDepths function returns the array of depths that
are available on the specified screen.  If the specified
screen_number is valid and sufficient memory for the array
can be allocated, XListDepths sets count_return to the
number of available depths.  Otherwise, it does not set
count_return and returns NULL.  To release the memory
allocated for the array of depths, use

The DefaultGC macro returns the default GC for the root
window of the specified screen.

The DefaultRootWindow macro returns the root window for the
default screen.

The DefaultScreenOfDisplay macro returns the default screen
of the specified display.

The DefaultScreen macro returns the default screen number
referenced in the XOpenDisplay routine.

The DefaultVisual macro returns the default visual type for
the specified screen.

The DisplayCells macro returns the number of entries in the
default colormap.

The DisplayPlanes macro returns the depth of the root window
of the specified screen.

The DisplayString macro returns the string that was passed
to XOpenDisplay when the current display was opened.

The XMaxRequestSize function returns the maximum request
size (in 4‐byte units) supported by the server without using
an extended‐length protocol encoding.  Single protocol
requests to the server can be no larger than this size
unless an extended‐length protocol encoding is supported by
the server.  The protocol guarantees the size to be no
smaller than 4096 units (16384 bytes).  Xlib automatically
breaks data up into multiple protocol requests as necessary
for the following functions: and


The XExtendedMaxRequestSize function returns zero if the
specified display does not support an extended‐length
protocol encoding; otherwise, it returns the maximum request
size (in 4‐byte units) supported by the server using the
extended‐length encoding.  The Xlib functions and XSetRegion
will use the extended‐length encoding as necessary, if
supported by the server.  Use of the extended‐length
encoding in other Xlib functions (for example, is permitted
but not required; an Xlib implementation may choose to split
the data across multiple smaller requests instead.

The LastKnownRequestProcessed macro extracts the full serial
number of the last request known by Xlib to have been
processed by the X server.

The NextRequest macro extracts the full serial number that
is to be used for the next request.

The ProtocolVersion macro returns the major version number
(11) of the X protocol associated with the connected

The ProtocolRevision macro returns the minor protocol
revision number of the X server.

The QLength macro returns the length of the event queue for
the connected display.

The RootWindow macro returns the root window.

The ScreenCount macro returns the number of available

The ScreenOfDisplay macro returns a pointer to the screen of
the specified display.

The ServerVendor macro returns a pointer to a null‐
terminated string that provides some identification of the
owner of the X server implementation.

The VendorRelease macro returns a number related to a
vendor’s release of the X server.

BlackPixelOfScreen(3), ImageByteOrder(3), IsCursorKey(3),
Xlib − C Language X Interface