XCreateWindow, XCreateSimpleWindow, XSetWindowAttributes - create
   windows and window attributes structure


   Window XCreateWindow(Display *display, Window parent, int x, int y,
          unsigned int width, unsigned int height, unsigned int
          border_width, int depth, unsigned int class, Visual *visual,
          unsigned long valuemask, XSetWindowAttributes *attributes);

   Window XCreateSimpleWindow(Display *display, Window parent, int x, int
          y, unsigned int width, unsigned int height, unsigned int
          border_width, unsigned long border, unsigned long background);


             Specifies the structure from which the values (as specified
             by the value mask) are to be taken.  The value mask should
             have the appropriate bits set to indicate which attributes
             have been set in the structure.

             Specifies the background pixel value of the window.

   border    Specifies the border pixel value of the window.

             Specifies the width of the created window's border in pixels.

   class     Specifies the created window's class.  You can pass
             InputOutput, InputOnly, or CopyFromParent.  A class of
             CopyFromParent means the class is taken from the parent.

   depth     Specifies the window's depth.  A depth of CopyFromParent
             means the depth is taken from the parent.

   display   Specifies the connection to the X server.

   parent    Specifies the parent window.

   valuemask Specifies which window attributes are defined in the
             attributes argument.  This mask is the bitwise inclusive OR
             of the valid attribute mask bits.  If valuemask is zero, the
             attributes are ignored and are not referenced.

   visual    Specifies the visual type.  A visual of CopyFromParent means
             the visual type is taken from the parent.

   height    Specify the width and height, which are the created window's
             inside dimensions and do not include the created window's

   y         Specify the x and y coordinates, which are the top-left
             outside corner of the window's borders and are relative to
             the inside of the parent window's borders.


   The XCreateWindow function creates an unmapped subwindow for a
   specified parent window, returns the window ID of the created window,
   and causes the X server to generate a CreateNotify event.  The created
   window is placed on top in the stacking order with respect to siblings.

   The coordinate system has the X axis horizontal and the Y axis vertical
   with the origin [0, 0] at the upper-left corner.  Coordinates are
   integral, in terms of pixels, and coincide with pixel centers.  Each
   window and pixmap has its own coordinate system.  For a window, the
   origin is inside the border at the inside, upper-left corner.

   The border_width for an InputOnly window must be zero, or a BadMatch
   error results.  For class InputOutput, the visual type and depth must
   be a combination supported for the screen, or a BadMatch error results.
   The depth need not be the same as the parent, but the parent must not
   be a window of class InputOnly, or a BadMatch error results.  For an
   InputOnly window, the depth must be zero, and the visual must be one
   supported by the screen.  If either condition is not met, a BadMatch
   error results.  The parent window, however, may have any depth and
   class.  If you specify any invalid window attribute for a window, a
   BadMatch error results.

   The created window is not yet displayed (mapped) on the user's display.
   To display the window, call XMapWindow.  The new window initially uses
   the same cursor as its parent.  A new cursor can be defined for the new
   window by calling XDefineCursor.  The window will not be visible on the
   screen unless it and all of its ancestors are mapped and it is not
   obscured by any of its ancestors.

   XCreateWindow can generate BadAlloc BadColor, BadCursor, BadMatch,
   BadPixmap, BadValue, and BadWindow errors.

   The XCreateSimpleWindow function creates an unmapped InputOutput
   subwindow for a specified parent window, returns the window ID of the
   created window, and causes the X server to generate a CreateNotify
   event.  The created window is placed on top in the stacking order with
   respect to siblings.  Any part of the window that extends outside its
   parent window is clipped.  The border_width for an InputOnly window
   must be zero, or a BadMatch error results.  XCreateSimpleWindow
   inherits its depth, class, and visual from its parent.  All other
   window attributes, except background and border, have their default

   XCreateSimpleWindow can generate BadAlloc, BadMatch, BadValue, and
   BadWindow errors.


   The XSetWindowAttributes structure contains:

   /* Window attribute value mask bits */

   #define   CWBackPixmap                (1L<<0)
   #define   CWBackPixel                 (1L<<1)
   #define   CWBorderPixmap              (1L<<2)
   #define   CWBorderPixel               (1L<<3)
   #define   CWBitGravity                (1L<<4)
   #define   CWWinGravity                (1L<<5)
   #define   CWBackingStore              (1L<<6)
   #define   CWBackingPlanes             (1L<<7)
   #define   CWBackingPixel              (1L<<8)
   #define   CWOverrideRedirect          (1L<<9)
   #define   CWSaveUnder                 (1L<<10)
   #define   CWEventMask                 (1L<<11)
   #define   CWDontPropagate             (1L<<12)
   #define   CWColormap                  (1L<<13)
   #define   CWCursor                    (1L<<14)
   /* Values */

   typedef struct {
           Pixmap background_pixmap;       /* background, None, or ParentRelative */
           unsigned long background_pixel; /* background pixel */
           Pixmap border_pixmap;           /* border of the window or CopyFromParent */
           unsigned long border_pixel;     /* border pixel value */
           int bit_gravity;        /* one of bit gravity values */
           int win_gravity;        /* one of the window gravity values */
           int backing_store;      /* NotUseful, WhenMapped, Always */
           unsigned long backing_planes;   /* planes to be preserved if possible */
           unsigned long backing_pixel;    /* value to use in restoring planes */
           Bool save_under;        /* should bits under be saved? (popups) */
           long event_mask;        /* set of events that should be saved */
           long do_not_propagate_mask;     /* set of events that should not propagate */
           Bool override_redirect; /* boolean value for override_redirect */
           Colormap colormap;      /* color map to be associated with window */
           Cursor cursor;          /* cursor to be displayed (or None) */
   } XSetWindowAttributes;

   For a detailed explanation of the members of this structure, see Xlib -
   C Language X Interface.


   BadAlloc  The server failed to allocate the requested resource or
             server memory.

   BadColor  A value for a Colormap argument does not name a defined

   BadCursor A value for a Cursor argument does not name a defined Cursor.

   BadMatch  The values do not exist for an InputOnly window.

   BadMatch  Some argument or pair of arguments has the correct type and
             range but fails to match in some other way required by the

   BadPixmap A value for a Pixmap argument does not name a defined Pixmap.

   BadValue  Some numeric value falls outside the range of values accepted
             by the request.  Unless a specific range is specified for an
             argument, the full range defined by the argument's type is
             accepted.  Any argument defined as a set of alternatives can
             generate this error.

   BadWindow A value for a Window argument does not name a defined Window.


   XChangeWindowAttributes(3), XConfigureWindow(3), XDefineCursor(3),
   XDestroyWindow(3), XMapWindow(3), XRaiseWindow(3), XUnmapWindow(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.