• avoid CDE to overwrite the application color settings in order to apply the current color scheme
*useColorObj: False
 
• on Solaris, the OpenWindows Desktop access can be disabled from dtlogin by creating an empty /etc/dt/config/C/Xresources.d/Xresources.ow file.

• retrieve Xlib version (in Xlib.h)
#define XlibSpecificationRelease 6
 
• retrieve Xt version (in Intrinsic.h)
#define XtSpecificationRelease 6

• retrieve Motif version (in Xm.h)
#define XmVERSION       2
#define XmREVISION      1
#define XmUPDATE_LEVEL  0
#define XmVersion       (XmVERSION * 1000 + XmREVISION)
#define XmVERSION_STRING "@(#)Motif Version 2.1.0"

• the keysym list can be found in
/usr/X11R6/include/X11/keysymdef.h
the symbols are in
/usr/X11R6/lib/X11/XKeysymDB

• to fix incorrect keys
#> xmodmap -pk
find the incorrect keycode's and fix them by (for example)
#> xmodmap -e "keycode 16 = egrave 7 grave"
#> xmodmap -e "keycode 18 = ccedilla 9 asciicircum"
#> xmodmap -e "keycode 19 = agrave 0 at"
#> xmodmap -e "keycode 20 = parenright degree bracketright"
#> xmodmap -e "keycode 34 = dead_circumflex dead_diaeresis"
#> xmodmap -e "keycode 35 = dollar sterling paragraph"
#> xmodmap -e "keycode 48 = ugrave percent"
#> xmodmap -e "keycode 49 = twosuperior"
#> xmodmap -e "keycode 51 = asterisk mu"
#> xmodmap -e "keycode 61 = exclam section"
(put these commands in ~/.xinitrc)

• to find the keycode of a key
#> xev
put the cursor in the xev window and type the key
 
• key compositions are defined in
/usr/X11R6/lib/X11/locale/iso8859-1/Compose

• RGB values for the named colors
/usr/X11R6/lib/X11/rgb.txt
 
• set the default visual to 24 bits on both screen (CDE on Solaris), in /etc/dt/config/Xservers:
  :0 Local local_uid@console root /usr/openwin/bin/Xsun -dev /dev/fbs/ffb0 defclass TrueColor defdepth 24 -dev /dev/fbs/ffb1 defclass TrueColor defdepth 24

• xfs: font server
 
• xfsinfo (XFree86) / fsinfo (Solaris): display information about the font server
 
• fslsfonts: list the fonts available on a font server
 
• fsadmin: enable/disable inetd to start the font server (on Solaris)
  
 
• showfont: display information about a font available on a font server
 
• xfd: display a font
#> xfd -fn fixed
 
• xlsfonts: list the font available to the X server
 
• xfontsel: graphical font selector
 
• a client wanting to connect to a font server must define the environment variable FONTSERVER
#> setenv FONTSERVER tcp/fontservername:port
 
• add the font server to the font path
#> xset fp+ tcp/fontservername:port

Resources:

• add a resource to the X server
echo '*useColorObj:False' | xrdb -merge
 
• remove some resources from the X server
#> xrdb -query | egrep -v '^\*.*Preset(Lab|WL|WW)[1-6]:.*$' | xrdb -load

Overlays:

• overlay visual information is stored in the SERVER_OVERLAY_VISUALS property of the root window

• Motif on Solaris
CC foo.c -I/usr/dt/include -I/usr/openwin/include -L/usr/dt/lib -lXm -L/usr/openwin/lib -lXmu -lXt -lXext -lX11

• x11perf
  

• xterm sets the environment variable $WINDOWID to the id of its X window
 
• ConnectionNumber returns the file descriptors of the server/client X socket.
XInternalConnectionNumbers returns the file numbers of other internal connections.
 
• maximum request sizes
long n=XMaxRequestSize(display);

max nb of points	XDrawLines	n-3
	XFillPolygon	n-4
max nb of lines
max nb of segments	XDrawSegments	(n-3)/2
max nb of rectangles	XFillRectangles XDrawRectangles	(n-3)/2
max nb of arcs	XFillArcs XDrawArcs	(n-3)/3

retrieve an application context
XtAppContext XtWidgetToApplicationContext(Widget w)
XtAppContext XtDisplayToApplicationContext(Display *display)

retrieve a display

Display *DisplayOfScreen(Screen *screen)	macro
Display *XDisplayOfScreen(Screen *screen)	routine
Display *XtDisplay(Widget w)	macro for widgets
Display *XtDisplayOfObject(Widget w)	routine for widgets or gadgets (in this case, go up the widget hierarchy up to a widget and return its display)

retrieve a window

Window XtWindow(Widget w)

Window XtWindowOfObject(Widget w)

Window RootWindow(Display *display, int screen_number)

Window XRootWindow(Display *display, int screen_number)

Window DefaultRootWindow(Display *display)

Window XDefaultRootWindow(Display *display)

Window RootWindowOfScreen(Screen *screen)

Window XRootWindowOfScreen(Screen *screen)

retrieve a screen

Screen *XtScreen(Widget w)

Screen *XtScreenofObject(Widget w)

Screen *ScreenOfDisplay(Display *display, int screen_number)

Screen *XScreenOfDisplay(Display *display, int screen_number)

Screen *DefaultScreenOfDisplay(Display *display)

Screen *XDefaultScreenOfDisplay(Display *display)

retrieve a widget

Widget XtNameToWidget(Widget root, String name)

Widget XtWindowToWidget(Display *display, Window window)

• in X:
• XInitThreads initializes Xlib support for concurrent threads. It must be the first called Xlib routine.
• XLockDisplay locks the display access for the other threads. The lock is a counter (XLockDisplay can be called several times, XUnlockDisplay must be called the same numbers of times to unlock the access to the display).
• in Xt:
• XtToolkitThreadInitialize must be called before XtAppInitialize, XtSetLanguageProc, XtOpenApplication or XtCreateApplicationContext. It may be called before of after XtToolkitInitialize. It may be called several times, but not concurrently from several threads.
• XtAppLock locks the application context. It is implicitly called by Motif and Xt functions that take an application context, a widget or a display as a parameter. But it may be necessary to call it when several operations must be done attomically (e.g. getting the value of a resource, testing it and modifying it if necessary; or getting the XmNchildren, XnMselectedItems, XmNsource... of a widget and manipulating them).
• XtProcessLock locks the global data structures.
• XtAppLock and XtProcessLock may be called several times, XtAppUnlock and XtProcessUnlock must be called the same number of times to unlock.
• To lock the application context and global data at the same time:
XtAppLock
XtProcessLock
... code ...
XtProcessUnlock
XtAppUnlock
• When multiple threads call into event management functions concurrently, they return from these functions in FIFO order.
This enables a thread which is not the input processing thread to popup and manage an error message:
XtAppContext app;
Widget error_dialog;
XEvent event;
XtAppLock(app); /* Lock the AppContext */
XtPopup(error_dialog, XtGrabExclusive); /* popup error dialog */
do {/* Take over input processing */
        XtAppNextEvent(app, &event);
        if(/* some boolean condition involving event */)
                XtDispatchEvent(&event);
} while(/* some boolean condition */)
XtAppUnlock(app);

Last update: December 22^nd, 2004 - Laurent