5.5. Your first X Program   

You can now create your first X Window System program (see later to retrieve it):

  #include <X11/Xlib.h>                         /* X library */

  #include <stdio.h>                            /* std input-output */

  #include <X11/Xutil.h>                        /* X utilities */


  main (argc, argv)

  int argc;

  char **argv;

  {

  Display               *myDisplay;             /* pointer to the display */

  int                   myScreen;               /* screen we are using */

  int                   myDepth;                /* colour plane depth */

  XSetWindowAttributes  myWindowAttributes;     /* structure of window attibutes */

  unsigned long         myWindowMask;           /* mask for window attributes */

  Window                myWindow;               /* window structure */

  XSizeHints            theSizeHints;           /* window hints for window manger */

  int                   x       = 200;          /* x top left corner of window */

  int                   y       = 150;          /* y top left corner of window */

  unsigned int          width   = 850;          /* width of the window */

  unsigned int          height  = 700;          /* height of the window */

  int                   border_width = 20;      /* border width of the window */


        myDisplay = XOpenDisplay ("");

        if (myDisplay == NULL)

        {

                fprintf (stderr,

                        "ERROR: Could not open a connection to X on display %s\n",

                XDisplayName (NULL));

                exit (0);

        }


        myScreen = DefaultScreen (myDisplay);


        myDepth = DefaultDepth (myDisplay, myScreen);


        myWindowAttributes.border_pixel = BlackPixel (myDisplay, myScreen);

        myWindowAttributes.background_pixel = WhitePixel (myDisplay, myScreen);

        myWindowAttributes.override_redirect = True;


        myWindowMask = CWBackPixel | CWBorderPixel | CWOverrideRedirect;


        myWindow = XCreateWindow (myDisplay,

                                        RootWindow (myDisplay, myScreen),

                                        x, y, width, height, border_width,

                                        myDepth, InputOutput, CopyFromParent,

                                        myWindowMask, &myWindowAttributes);


        theSizeHints.flags      = PPosition | PSize;    /* set mask for the hints */

        theSizeHints.x          = x;                    /* x position */

        theSizeHints.y          = y;                    /* y position */

        theSizeHints.width      = width;                /* width of the window */

        theSizeHints.height     = height;               /* height of the window */


        XSetWMNormalHints (myDisplay, myWindow, &theSizeHints);


        XMapWindow (myDisplay, myWindow);


        XFlush (myDisplay);


  /*-----------------------------------------------------------------------------

        SLEEP FOR 10 SECONDS

  -----------------------------------------------------------------------------*/


        sleep(10);


        XDestroyWindow (myDisplay, myWindow);

        XCloseDisplay (myDisplay);


        exit (0);

}

LOCAL_LIBRARIES = $(XLIB) -lm

           FILE = simplewindow

           SRCS = $(FILE).c

           OBJS = $(FILE).o


ComplexProgramTarget($(FILE))

After retrieving and saving the code plus Imakefile, you should be able to type:
xmkmf -a ; make FILE=simplewindow
This will produce the executable called simplewindow.

It is possible to execute a (different) simplewindow program and display it on your screen. To run it, your system must be running X and the server control is set to xhost www.cs.curtin.edu.au/. Also it will not work if you are using a proxy server or you are running your browser on a machine different from the one you are displaying it on. Many example programs are available