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

   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

   The WhitePixel macro returns the white pixel value for the specified

   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 XFree.

   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

   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

   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: XDrawPoints, XDrawRectangles, XDrawSegments, XFillArcs,
   XFillRectangles, and XPutImage.

   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 XDrawLines, XDrawArcs, XFillPolygon, XChangeProperty,
   XSetClipRectangles, 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,
   XDrawPoints, XDrawRectangles, XDrawSegments, XFillArcs,
   XFillRectangles, XPutImage) 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 display.

   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 screens.

   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

   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


Personal Opportunity - Free software gives you access to billions of dollars of software at no cost. Use this software for your business, personal use or to develop a profitable skill. Access to source code provides access to a level of capabilities/information that companies protect though copyrights. Open source is a core component of the Internet and it is available to you. Leverage the billions of dollars in resources and capabilities to build a career, establish a business or change the world. The potential is endless for those who understand the opportunity.

Business Opportunity - Goldman Sachs, IBM and countless large corporations are leveraging open source to reduce costs, develop products and increase their bottom lines. Learn what these companies know about open source and how open source can give you the advantage.

Free Software

Free Software provides computer programs and capabilities at no cost but more importantly, it provides the freedom to run, edit, contribute to, and share the software. The importance of free software is a matter of access, not price. Software at no cost is a benefit but ownership rights to the software and source code is far more significant.

Free Office Software - The Libre Office suite provides top desktop productivity tools for free. This includes, a word processor, spreadsheet, presentation engine, drawing and flowcharting, database and math applications. Libre Office is available for Linux or Windows.

Free Books

The Free Books Library is a collection of thousands of the most popular public domain books in an online readable format. The collection includes great classical literature and more recent works where the U.S. copyright has expired. These books are yours to read and use without restrictions.

Source Code - Want to change a program or know how it works? Open Source provides the source code for its programs so that anyone can use, modify or learn how to write those programs themselves. Visit the GNU source code repositories to download the source.


Study at Harvard, Stanford or MIT - Open edX provides free online courses from Harvard, MIT, Columbia, UC Berkeley and other top Universities. Hundreds of courses for almost all major subjects and course levels. Open edx also offers some paid courses and selected certifications.

Linux Manual Pages - A man or manual page is a form of software documentation found on Linux/Unix operating systems. Topics covered include computer programs (including library and system calls), formal standards and conventions, and even abstract concepts.