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Archive-name: Xt-FAQ Version: $Id: FAQ-Xt,v 1.44 1995/03/27 15:22:22 ware Exp ware $ The X Toolkit Intrinsics F.A.Q A monthly posting This article contains the answers to some Frequently Asked Questions (FAQ) from comp.windows.x about the X Toolkit Intrinsics. To submit questions (preferably with an answer) send email to: ware@cis.ohio-state.edu or you can find out more about me as: http://www.cis.ohio-state.edu/~ware This FAQ is available on the archive site rtfm.mit.edu in the directory: file://rtfm.mit.edu/pub/usenet/comp.answers/Xt-FAQ The name under which a FAQ is archived appears in the Archive-name line at the top of the article. This FAQ is archived as Xt-FAQ. It is also archived in file://ftp.x.org:/contrib/faqs/FAQ-Xt. All code fragments are public domain. Contents 0. Xt Glossary 1. Software Versions 2. Related FAQ's 3. Why does my app core dump when I use signals/alarms/cthreads? 4. How do I use a different visual than the default? 5. Which visual should an application use? 6. Why do only Shell widgets have a Visual? 7. Which visual, depth and colormap do Shells inherit? 8. I've done all the above and I still get a BadMatch error. Why? 9. Why doesn't my widget get destroyed when I call XtDestroyWidget()? 10. How do I exit but still execute the DestroyCallbacks? 11. How do I resize a Shell widget? 12. Why can't XtAppAddInput() handle files? 13. What good books and magazines are there on Xt? 14. What Widgets are available? 15. What alternatives to the Intrinsics are there? 16. How do I pass a float value to XtSetValues? 17. How do I write a resource converter? 18. How do I open multiple displays? 19. What changed from R3 to R4 to R5? 20. Where are the resources loaded from? 21. What order are callbacks executed in? 22. How do I know if a widget is visible? 23. How do I reparent a widget in Xt, i.e. XtReparentWidget()? 24. Why use XtMalloc, XtFree, etc? 25. How to debug an Xt application? 26. Why don't XtAddInput(), XtAddTimeout() and XtAddWorkProc() work? 27. What is and how can I implement drag and drop? 28. How can I add a C++ member function as a widget callback? 29. How can I identify the children of a manager widget? 30. Can I use XtMoveWidget(), ... to move widgets I created? 31. Why is XtGetValues() on XtNx, XtNy of my top level shell wrong? 32. Why do some people use XmNas resource names? 33. How do I make my life easier when designing an application? 34. Why can't I override translations? Only the first item works. 35. Why do I get "Warning: Widget class version mismatch"? 36. Where can I get a good file-selector widget? 37. Where can I find a hypertext widget or source code? 38. What widget is appropriate to use as a drawing canvas? 39. What is this link problem with _get_wmShellWidgetClass, XtInherit? 40. Why does XtGetValues not work for me (sic)? 41. Is this a memory leak in the X11R4 XtDestroyWidget()?! 42. Is this a memory leak in the X11R4 deletion of work procs?! 43. How do I query the user synchronously using Xt? 44. How do I simulate a button press/release event for a widget? 45. How to use Fallback resources (can I specify colors)? 46. What is the preferred way of setting the application resources? 47. How to get rid of that annoying flicker during updates? 48. How are created, managed, mapped, realized, etc. related? 49. How to use the String definition from a C++ library? ---------------------------------------------------------------------- Subject: 0. Xt Glossary ---------------------------------------------------------------------- o The Xt Intrinsics implement an object oriented interface to C code to allow useful graphical components to be created. Included with this are classes that provide the base functionality: Object, RectObj, Core, Composite, Constraint, Shell, OverrideShell, WMShell, etc. The terms "Xt" and "Intrinsics" are used interchangeably, however, they are used very precisely to mean a specific library of the X window system. In particular, it does not include the Athena, Motif, OLIT or any other widget set. Without further widgets the Intrinsics are not especially useful. o A widget refers to a user interface abstraction created via Xt. The precise use, is any object that is a subclass of the Core class. It is used loosely to refer to anything that is a subclass of the Object class although these are more accurately called windowless widgets or gadgets. o Xlib is the C interface to the X11 protocol. It is one layer below the Xt Intrinsics. Typically a widget uses relatively few Xlib functions because Xt provides most such services although an understanding of Xlib helps with problems. ---------------------------------------------------------------------- Subject: 1. Software Versions ---------------------------------------------------------------------- The following are the latest versions of Xt based software: _____________________________________________________________ Software Version Released Next Expected _____________________________________________________________ X11R4 patch 18 (none) X11R5 patch 26 11/3/93 (none) X11R6 patch 13 11/3/95 (see R6.1) X11R6.1 patch 1 3/11/96 soon Athena Widgets (see X11R6) Motif 2.0 6/21/94 ?? OLIT ?? ?? ?? Xtra 2.5 6/15/92 ?? Xw X11R4 (none) Xcu X11R5 (none) fwf 4.1 5/24/96 ?? _____________________________________________________________ ---------------------------------------------------------------------- Subject: 2. Related FAQ's ---------------------------------------------------------------------- David B. Lewis (uunet!craft!faq) maintains the FAQ on X. It is posted monthly on comp.windows.x and located in: file://ftp.x.org/contrib/faqs/FAQ. Liam R. E. Quin (lee@sq.sq.com) posts an FAQ list on Open Look to comp.windows.x. Ken Sall (ksall@cen.com) posts an FAQ list on Motif to comp.windows.x.motif. it is also in file://ftp.x.org/contrib/faqs/Motif-FAQ Pete Ware (ware@cis.ohio-state.edu) posts an FAQ list for comp.windows.x.intrinsics; it is in file://ftp.x.org/contrib/faqs/FAQ-Xt John L. Cwikla (cwikla@wri.com) posts an FAQ list that contains freely available widgets; it is in: file://ftp.x.org/contrib/faqs/Widget.FAQ ---------------------------------------------------------------------- Subject: 3. Why does my app core dump when I use signals/alarms/cthreads? ---------------------------------------------------------------------- In brief, Xlib, Xt and most widget sets have no mutual exclusion for critical sections. Any interrupt handler is likely to leave one of the above libraries in an inconsistent state -- such as all the appropriate flags not yet set, dangling pointers, in the middle of a list traversal, etc. Note that the ANSI C standard points out that behavior of a signal handler is undefined if the signal handler calls any function other than signal() itself, so this is not a problem specific to Xlib and Xt; the POSIX specification mentions other functions which may be called safely but it may not be assumed that these functions are called by Xlib or Xt functions. The only safe way to deal with signals is to set a flag in the interrupt handler. This flag later needs to be checked either by a work procedure or a timeout callback. It is incorrect to add either of these in the interrupt handler. As another note, it is dangerous to add a work procedure that never finishes. This effectively preempts any work procedures previously added and so they will never be called. Another option is to open a pipe, tell the event loop about the read end using XtAppAddInput() and then the signal handler can write a byte to the write end of the pipe for each signal. However, this could deadlock your process if the pipe fills up. Why don't the Intrinsics deal with this problem? Primarily because it is supposed to be a portable layer to any hardware and operating system. Is that a good enough reason -- I don't think so. Note: the article in The X Journal 1:4 and the example in O'Reilly Volume 6 are in error. ---------------------------------------------------------------------- Subject: 4.! How do I use a different visual than the default? ---------------------------------------------------------------------- This requires a more complicated answer than it should. A window has three things that are visual specific -- the visual, colormap and border pixmap. All widgets have their own Colormap and BorderPixmap resource; only shell widgets have Visual resources (another questions deals with why shells have a Visual). The default value of these resources is CopyFromParent which does exactly what it says. In the shell widget CopyFromParent gets evalulated as DefaultVisualOfScreen and DefaultColormapOfScreen. When any one of the three resources is not properly set, a BadMatch error occurs when the window is created. They are not properly set because each of the values depends on the visual being used. How to get this to work? There are two parts to the answer. The first is if you want an application to start with a particular visual and the second is if you want a particular shell within an application to start with a different visual. The second is actually easier because the basic information you need is available. The first is a little harder because you'll need to initialize much of the toolkit yourself in order to determine the needed information. /* * Some sample code to start up an application using something other * than the default visual. * * To compile: * cc -g visual.c -o visual -lXaw -lXmu -lXt -lXext -lX11 -lm * * To run: * ./visual -geometry 300x300 -depth 24 -visual StaticColor -fg blue -bg yellow * * you need to move the mouse to get the particular visuals colormap * to install. */ #include #include #include typedef struct { Visual *visual; int depth; } OptionsRec; OptionsRec Options; XtResource resources[] = { {"visual", "Visual", XtRVisual, sizeof (Visual *), XtOffsetOf (OptionsRec, visual), XtRImmediate, NULL}, {"depth", "Depth", XtRInt, sizeof (int), XtOffsetOf (OptionsRec, depth), XtRImmediate, NULL}, }; XrmOptionDescRec Desc[] = { {"-visual", "*visual", XrmoptionSepArg, NULL}, {"-depth", "*depth", XrmoptionSepArg, NULL} }; int main (argc, argv) int argc; char **argv; { XtAppContext app; /* the application context */ Widget top; /* toplevel widget */ Display *dpy; /* display */ char **xargv; /* saved argument vector */ int xargc; /* saved argument count */ Colormap colormap; /* created colormap */ XVisualInfo vinfo; /* template for find visual */ XVisualInfo *vinfo_list; /* returned list of visuals */ int count; /* number of matchs (only 1?) */ Arg args[10]; Cardinal cnt; char *name = "test"; char *class = "Test"; /* * save the command line arguments */ xargc = argc; xargv = (char **) XtMalloc (argc * sizeof (char *)); bcopy ((char *) argv, (char *) xargv, argc * sizeof (char *)); /* * The following creates a _dummy_ toplevel widget so we can * retrieve the appropriate visual resource. */ cnt = 0; top = XtAppInitialize (&app, class, Desc, XtNumber (Desc), &argc, argv, (String *) NULL, args, cnt); dpy = XtDisplay (top); cnt = 0; XtGetApplicationResources (top, &Options, resources, XtNumber (resources), args, cnt); cnt = 0; if (Options.visual && Options.visual != DefaultVisualOfScreen (XtScreen (top))) { XtSetArg (args[cnt], XtNvisual, Options.visual); ++cnt; /* * Now we create an appropriate colormap. We could * use a default colormap based on the class of the * visual; we could examine some property on the * rootwindow to find the right colormap; we could * do all sorts of things... */ colormap = XCreateColormap (dpy, RootWindowOfScreen (XtScreen (top)), Options.visual, AllocNone); XtSetArg (args[cnt], XtNcolormap, colormap); ++cnt; /* * Now find some information about the visual. */ vinfo.visualid = XVisualIDFromVisual (Options.visual); vinfo_list = XGetVisualInfo (dpy, VisualIDMask, &vinfo, &count); if (vinfo_list && count > 0) { XtSetArg (args[cnt], XtNdepth, vinfo_list[0].depth); ++cnt; XFree ((XPointer) vinfo_list); } } XtDestroyWidget (top); /* * Now create the real toplevel widget. */ XtSetArg (args[cnt], XtNargv, xargv); ++cnt; XtSetArg (args[cnt], XtNargc, xargc); ++cnt; top = XtAppCreateShell ((char *) NULL, class, applicationShellWidgetClass, dpy, args, cnt); /* * Display the application and loop handling all events. */ XtRealizeWidget (top); XtAppMainLoop (app); return (0); } You can also try: file://ftp.x.org/contrib/widget/AppPlusS.tar.Z The AppPlusShell adds the following to the application shell: 1) Visual/Colormap control thru resources 2) EditRes built in (can be turned on/off) 3) Catches the WM_DELETE_WINDOW It does this thru the following added resources: For 1: XtNvisualClass XtNusePrivateColormap XtNvisualID XtNapplicationDepth For 2: XtNallowEditRes For 3: XtNsaveYourselfCallback The algorithm is as follows, in this order: 1) if XtNvisualID is set try to use the visual with this id, if it exists. 2) if XtNapplicationDepth is set try to find a visual with that depth, otherwise set it to DefaultDepth(). This allows users to have: *applicationDepth: 24 which will be used if it exists. applicationDepth is needed instead of *depth, since, IMO, most users will want to do *depth: 24 which would screw up for any subwidgets, if there were no visual with a depth of 24. Note that the depth gets correctly set in the initialize too. 3) if XtNvisualClass is set then find the visual with the that class and the greatest depth. 4) if all else fails use the default visual/default depth. 5) if we the visualID == default visual id, and XtNusePrivateColormap is FALSE, then use the default colormap, otherwise, create an appropriate one. There only other thing of interest is if you define MOTIF the code uses some Motif functions instead of their X/Xt equivalents, but otherwise should work with pretty much any Xt widget set. I use a version of this code in our product, and so it has been used on just about every major U*x platform with success. ---------------------------------------------------------------------- Subject: 5. Which visual should an application use? ---------------------------------------------------------------------- This is a point that can be argued about but one opinion is there is no way for an application to know the appropriate visual -- it has to be specified by the user. If you disagree with this then your application probably falls into the category of always using the default visual or it is hardware specific and expects some particular visual such as 24bit TrueColor with an OverlayPlane extension (or some such). Why? No application runs in isolation. Depending on the way a server allocates resources I may not always want your application to run in TrueColor mode if it is going to mess up my other applications. I may be very upset if it chooses to run in GreyScale instead of PsuedoColor or just monochrome. As an example, on a low end color Sun server there are many different possible visuals: monochrome, 256 entry colormap, static gray, static color, and a 3/3/2 TrueColor. The SGI Iris's offer all the above plus 12 bit TrueColor, 24 bit TrueColor, an Overlay Plane. ---------------------------------------------------------------------- Subject: 6. Why do only Shell widgets have a Visual? ---------------------------------------------------------------------- This is strictly by convention. It makes it possible for an arbitrary widget to know that the visual it uses can be found by looking for the shell widget that is its ancestor and obtaining the visual of that shell. A widget can have its own visual resource. If it does, it must have its own realize method to use the visual when it calls XCreateWindow(). You should also make this a resource that can be obtained with XtGetValues() so other widgets can find it. A reasonable value is probably XtNvisual. ---------------------------------------------------------------------- Subject: 7. Which visual, depth and colormap do Shells inherit? ---------------------------------------------------------------------- The default value for these resources are set to CopyFromParent. This is interpreted as the DefaultColormapOfScreen(), DefaultDepthOfScreen() and the default visual of the screen if the widget has no parent -- i.e. it is an applicationShellWidgetClass and the root of your widget tree. If the parent of the widget is not null, then the shell copies colormap and depth from its parent and uses CopyFromParent as the visual. ---------------------------------------------------------------------- Subject: 8. I've done all the above and I still get a BadMatch error. Why? ---------------------------------------------------------------------- Some resource converters improperly cache references. This was especially true of X11R3 and earlier versions of Motif. ---------------------------------------------------------------------- Subject: 9. Why doesn't my widget get destroyed when I call XtDestroyWidget()? ---------------------------------------------------------------------- See section 2.8 of the Xt specification. It eventually does get destroyed, just not immediately. The Intrinsics destroy a widget in a two-phase process. First it and all of its children have a flag set that indicate it is being destroyed. It is then put on a list of widgets to be destroyed. This way any pending X events or further references to that widget can be cleaned up before the memory is actually freed. The second phase is then performed after all callbacks, event handlers, and actions have completed, before checking for the next X event. At this point the list is traversed and each widget's memory is actually free()'d, among other things. As some further caveats/trivia, the widgets may be destroyed if the Intrinsics determine that they have no further references to the widgets on the list. If so, then the phase 2 destruction occurs immediately. Also, if nested event loops are used, widgets placed on the destroy list before entering the inner event loop are not destroyed until returning to the outer event loop. ---------------------------------------------------------------------- Subject: 10. How do I exit but still execute the DestroyCallbacks? ---------------------------------------------------------------------- The problem is if a simple and entirely reasonable approach to exiting an application is used, such as calling exit() directly, then a widget may not have a chance to clean up any external state -- such as open sockets, temporary files, allocated X resources, etc. (this code for simplicity reasons assumes only a single toplevel widget): Widget ToplevelGet (gw) Widget gw; /* widget to find toplevel */ { Widget top; for (top = gw; XtParent (top); top = XtParent (top)) /* empty */; return (top); } void ExitCallback (gw, closure, call_data) Widget gw; /* widget */ XtPointer closure; /* data the app specified */ XtPointer call_data; /* widget specific data */ { Widget toplevel; toplevel = ToplevelGet (gw); XtUnmapWidget (toplevel); /* make it disappear quickly */ XtDestroyWidget (toplevel); exit (0); } One can see that the above code exit's immediately after destroying the toplevel widget. The trouble is the phase 2 destruction may never occur. This works for most widgets and most applications but will not work for those widgets that have any external state. You might think that since it works now it will always work but remember that part of the reason an object oriented approach is used is so one can be ignorant of the implementation details for each widget. Which means that the widget may change and someday require that some external state is cleaned up by the Destroy callbacks. One alternative is to modify ExitCallback() to set a global flag and then test for that flag in a private event loop. Or try the following code: #include extern Widget ToplevelGet ( #if NeedFunctionPrototypes Widget gw #endif ); extern Boolean ExitWorkProc ( #if NeedFunctionPrototypes XtPointer closure #endif ); extern void ExitCallback ( #if NeedFunctionPrototypes Widget gw, XtPointer closure, XtPointer call_data #endif ); Widget ToplevelGet (gw) Widget gw; /* widget to find toplevel */ { Widget top; for (top = gw; XtParent (top); top = XtParent (top)) /* empty */; return (top); } void ExitCallback (gw, closure, call_data) Widget gw; /* widget */ XtPointer closure; /* data the app specified */ XtPointer call_data; /* widget specific data */ { Widget toplevel; toplevel = ToplevelGet (gw); XtUnmapWidget (toplevel); /* make it disappear quickly */ XtDestroyWidget (toplevel); XtAppAddWorkProc (XtWidgetToApplicationContext (gw), ExitWorkProc, (XtPointer) NULL); } Boolean ExitWorkProc (closure) XtPointer closure; { exit (0); /*NOTREACHED*/ } ExitCallback() adds a work procedure that will get called when the application is next idle -- which happens after all the events are processed and the destroy callbacks are executed. ---------------------------------------------------------------------- Subject: 11. How do I resize a Shell widget? ---------------------------------------------------------------------- After it is realized, one doesn't resize a Shell widget. The proper thing is to resize the currently managed child of the Shell widget using XtSetValues(). The geometry change is then propagated to the Shell which asks the window manager which may or may not allow the request. However, the Shell must have the resource XtNallowShellResize set to True otherwise it will not even ask the window manager to grant the request and the Shell will not resize. To change the position of a Shell, use XtSetValues() on the Shell, not the child, and within the limits of the window manager it should be granted. ---------------------------------------------------------------------- Subject: 12. Why can't XtAppAddInput() handle files? ---------------------------------------------------------------------- It does, however Unix semantics for when I/O is ready for a file does not fit most peoples' intuitive model. In Unix terms a file descriptor is ready for reading whenever the read() call would not block, ignoring the setting of optional flags that indicate not to block. This works as expected for terminals, sockets and pipes. For a file the read() will always return but the return indicates an EOF -- i.e. no more data. The result is the code in the Intrinsics always calls the input handler because it always thinks something is about to be read. The culprit is the select() system call or on SYSV based OS's it is the poll() system call. How to get around this on a Unix system? The best approach is to use another process to check for available input on the file. Use a pipe to connect the application with this other process and pass the file descriptor from the pipe to XtAppAddInput(). A suitable program on BSD systems is "tail -f filename". It's rumored that select() on some systems is not _completely_ reliable. In particular: - IBM AIX 3.1: this is one where it would work for a while (several thousand times) and then stop until some other event woke it up. This seemed to be the result of a race condition in the Kernel. IBM claims to have a fix for this. - Pyramid, doesn't work at all. - Ultrix (and possibly others where pipes are implemented as sockets), wasn't completely broken, but although the writing side wrote in 512 byte blocks the reading side received it all broken up as if it was being put into the pipe a byte at a time. You can waste a lot of time by reading small blocks (get raound it by detecting the situation and having select() ignore the pipe for 10 mseconds - by then it had been given the whole block). Note that all the above descriptions used Unix terminology such as read(), file descriptor, pipes, etc. This is an OS dependent area and may not be identical on all systems. However the Intrinsic designers felt it was a common enough operation that it should be included with part of the toolkit. Why they didn't also deal with signals at this point I don't know. ---------------------------------------------------------------------- Subject: 13.!What good books and magazines are there on Xt? ---------------------------------------------------------------------- I have a favorite that is the definitive reference. To my perspective it offers a reasonable introduction but also goes into the full details of the Intrinsics. When I started using it I was already familiar with Xt and the concepts behind it, so newcomers may or may not find it useful. I've always found it accurate and complete, which means it's 1000 pages. Asente, Paul J., and Swick, Ralph R., "X Window System Toolkit, The Complete Programmer's Guide and Specification", Digital Press, 1990, ISBN 1-55558-051-3, order number EY-E757E-DP; and by Prentice-Hall, ISBN 0-13-972191-6. Also available through DEC Direct at 1-800-DIGITAL. The other book I commonly recomend to novices is: Young, Doug. "The X Window System: Applications and Programming with Xt (Motif Version)," Prentice Hall, 1989 (ISBN 0-13-497074-8). (ISBN 0-13-972167-3) And of course O'Reilly has an entire series of manuals on X and Xt. O'Reilly ordering is 800-998-9938. In particular, Volume 5 is an Xt reference done in manual page style. The 3rd edition is extensively overhauled and goes far beyond the MIT manual pages. I'm finding it very useful. In particular, the permutted index and references to other manual pages help a great deal in chasing down related information. I read two periodicals, "The X Resource" and the "The X Journal". These are the only two dealing specifically with X. "The X Resource" is published quarterly, by O'Reilly, with one of the issues being the MIT X Consortium Technical Conference Proceedings. There is no advertising. I've found it informative with pretty good depth. For orders, call 1-800-998-9938, or email cathyr@ora.com. For editorial matters, email adrian@ora.com. Table of contents are posted at math.utah.edu in ~ftp/pub/tex/bib in TeX form and on ftp.uu.net in ~ftp/published/oreilly/xresource in ASCII form. "The X Journal" is a bimonthly trade rag with lots of advertising. The articles are informative and oriented toward a less technical audience. I read it more to see what's going on then with an expectation of learning a great deal (but remember, I represent a fairly small percentage of people). Also, they have a pretty good collection of people on the advisory board and as columnists. Call (908) 563-9033. For German readers try: Brede et.al. "Programmieren mit OSF/Motif" Addison-Wesley, Germany (ISBN 3-89319-211-5) It is a book which introduces Xt technics with motif widgets from an applications programmers point of view (no widget design stuff). ---------------------------------------------------------------------- Subject: 14. What Widgets are available? ---------------------------------------------------------------------- There are three popular widget sets: Athena - The set provided with X11. This is sufficient for most purposes but is on the ugly side. Recently, a 3d look is available for ftp on file://ftp.x.org/contrib/Xaw3d.tar.Z. Motif - From OSF available for a license fee and commonly shipped on many workstation vendors platforms (almost everyone but Sun). It looks good and works well but personally I think it is poorly implemented. OLIT - The Open Look Intrinsics Toolkit is a set of widgets implementing Sun's Open Look specification. Developed by AT&T. I've never used it so can't comment on its quality. I've heard rumours that it is a pain to actually get. In addition the following collection of widgets are also available: Xtra - a library of widgets for sale from Graphical Software Technology (310-328-9338). It includes bar graph, stacked bar graph, line graph, pie chart, xy plot, hypertext, help, spreadsheet, and data entry form widgets. I've never seen them so I can't comment. FWF - The Free Widget Foundation is attempting to collect a set of freely available widgets. Included are a Pixmap editor, FileDialog, and a few others. The current set of widgets can be obtained via anonymous ftp from the machine a.cs.uiuc.edu (128.174.252.1) in the file pub/fwf.shar.Z. Xcu - The Cornell University widgets from Gene Dykes. One of the early widget sets released. Provides a nice appearance for buttons and has a mini command language. Probably not so widely used. Xs - The Sony widget set. This was around during R3 days but seemed to disappear. It looked like it had promise. Xw - The HP widgets. The precursor to Motif. Originally written for R3 there exists diffs to get it to work under R4 & R5. Again, a pretty good widget set but has more or less died. The precursor to this was the Xray toolkit which was originally implemented for X10R4 and apparently provided much experience for the designers of Xt. Xo - A widget set I'm working on. It's still primitive but you can give it a try in archive.cis.ohio-state.edu:pub/Xo/* The following specialized widgets are also available: Tbl - Implements a tabular layout of widgets. Supports Motif widgets as children. Part of Wcl. Plots - The Athena Plotting widgets (not the Athena widgets). Contact gnb@bby.oz.au or joe@Athena.MIT.EDU. John L. Cwikla (cwikla@wri.com) posts an FAQ list that contains freely available widgets; it is in: file://ftp.x.org/contrib/faqs/Widget.FAQ A much more exciting version of this FAQ, complete with pictures, links, and more complete documentation is available at http://www.wri.com/~cwikla/widget ---------------------------------------------------------------------- Subject: 15. What alternatives to the Intrinsics are there? ---------------------------------------------------------------------- __________________________________________ Name Language Vendor __________________________________________ Xview C Sun OI C++ ParcPlace Interviews C++ Stanford Tcl/tk C ftp.cs.berkeley.edu __________________________________________ However much I like C and admire the skill in both designing and implementing the Intrinsics, hopefully some alternative will develop in the next 3-5 years that uses an object oriented language. Keep
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