* Re: Calling XtAppAddTimeOut, help
1999-05-30 0:00 Calling XtAppAddTimeOut, help John B. Matthews, M.D.
@ 1999-05-30 0:00 ` Paul Hussein
1999-06-01 0:00 ` dennison
1999-06-07 0:00 ` John
2 siblings, 0 replies; 4+ messages in thread
From: Paul Hussein @ 1999-05-30 0:00 UTC (permalink / raw)
Where is you app context coming from. Should it not be the app context for
the main app window ?
I am working on SGI with gnat Ada and C, and have just implemented a
timeout o.k.
However, I write the Motif code in C and interface to it.
Best approach would be to write it in C and get it working first, then
gradually move to Ada, one part at a time.
John B. Matthews, M.D. <matthewsj@deleteme.saic.com> wrote in message
news:matthewsj-ya023680003005990012190001@news.saic.com...
> Under IRIX 6.5, I'm trying to set up a callback using the X-windows
> function Xt.Intrinsic.XtAppAddTimeOut. For some reason, the code raises
> Program_Error when the call to XtAppAddTimeOut occurs. Example code
> follows. I've tried making my own binding and allocating more space to
> Xt.Intrinsic.XtAppStruct. The SGI binding appears to match the declaration
> in Intrinsic.h. A call to the obsolete function XtAddTimeOut succeeds, but
> the callback never excecutes. Any insights much appreciated; post or email
> (sans deleteme) is fine.
>
> Thanks in advance,
>
> John
>
> ----- gnatchop here ----
> -- gnatmake -g -n32 -mips3 timeout.adb -largs -lXm -lXt -lMrm -lX11
> with Ada.Unchecked_Conversion;
> with System;
> with Text_IO;
> with Timer_CB;
> with Xt.Intrinsic;
>
> procedure TimeOut is
>
> --- Convert a System.Address to an XtPointer
> function To_XtPointer is new Ada.Unchecked_Conversion (
> System.Address, Xt.Intrinsic.XtPointer);
>
> --- Timer static data
> App_Context : Xt.Intrinsic.XtAppContext := new Xt.Intrinsic.XtAppStruct;
> Timer_Id : Xt.Intrinsic.XtIntervalId := 0;
>
> begin
> --- Add a timer callback
> Timer_Id := Xt.Intrinsic.XtAppAddTimeOut ( -- dies here!
> App_Context => App_Context,
> Interval => 200, -- 200 msec
> Proc => Timer_CB.Timer_Callback'Access,
> Closure => To_XtPointer (Timer_Id'Address));
> Delay 10.0;
> Text_IO.Put_Line("Main ends.");
>
> end;
>
> package body Timer_CB is
>
> procedure Timer_Callback (
> Closure : Xt.Intrinsic.XtPointer;
> Id : access Xt.Intrinsic.XtIntervalId) is
> begin
> Text_IO.Put_Line("In callback.");
> end Timer_Callback;
>
> end;
>
> with Text_IO;
> with Xt.Intrinsic;
>
> package Timer_CB is
>
> procedure Timer_Callback (
> Closure : Xt.Intrinsic.XtPointer;
> Id : access Xt.Intrinsic.XtIntervalId);
> pragma Convention (C, Timer_Callback);
>
> end;
> ----- code ends -----
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: Calling XtAppAddTimeOut, help
1999-05-30 0:00 Calling XtAppAddTimeOut, help John B. Matthews, M.D.
1999-05-30 0:00 ` Paul Hussein
@ 1999-06-01 0:00 ` dennison
1999-06-07 0:00 ` John
2 siblings, 0 replies; 4+ messages in thread
From: dennison @ 1999-06-01 0:00 UTC (permalink / raw)
In article <matthewsj-ya023680003005990012190001@news.saic.com>,
matthewsj@deleteme.saic.com (John B. Matthews, M.D.) wrote:
> Under IRIX 6.5, I'm trying to set up a callback using the X-windows
> function Xt.Intrinsic.XtAppAddTimeOut. For some reason, the code
raises
> Program_Error when the call to XtAppAddTimeOut occurs. Example code
> --- Add a timer callback
> Timer_Id := Xt.Intrinsic.XtAppAddTimeOut ( -- dies here!
> App_Context => App_Context,
> Interval => 200, -- 200 msec
> Proc => Timer_CB.Timer_Callback'Access,
> Closure => To_XtPointer (Timer_Id'Address));
> Delay 10.0;
> Text_IO.Put_Line("Main ends.");
>
> end;
>
> package body Timer_CB is
>
> procedure Timer_Callback (
> Closure : Xt.Intrinsic.XtPointer;
> Id : access Xt.Intrinsic.XtIntervalId) is
> begin
> Text_IO.Put_Line("In callback.");
> end Timer_Callback;
>
> end;
>
> with Text_IO;
> with Xt.Intrinsic;
>
> package Timer_CB is
>
> procedure Timer_Callback (
> Closure : Xt.Intrinsic.XtPointer;
> Id : access Xt.Intrinsic.XtIntervalId);
> pragma Convention (C, Timer_Callback);
I've gotten this routine to work correctly before in Ada83, but of
course that doesn't mean much. Looking at your code I do notice a couple
of things (Hopefully deja won't screw up my formatting this time).
o You don't have a "pragma export (C, Timer_Callback)". That
might cause a problem.
o As written, the callback will never get called. For anything
to happen, you have to allow X to handle its events. This is typically
done by calling XtMainLoop(), or one of its subroutines.
o I don't see a call to XtAppInitialize. Without that call, your
App_Context is complete crap, and will probably cause your program to go
off into never-never land. I wouldn't have expected Program_Error to
result, but who knows?
I'd exepect your sample program to have a calling sequence similar to
the following:
XtAppInitialize()
XtAppAddTimeout()
XtMainLoop()
(Note that XtMainLoop will not return, so the program will have to be
killed somehow when you are done).
I highly suggest you get hold of volume 4 of the O'Reilly series of X
manuals. The rest of the series wouldn't be a bad idea either.
--
T.E.D.
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^ permalink raw reply [flat|nested] 4+ messages in thread* Re: Calling XtAppAddTimeOut, help
1999-05-30 0:00 Calling XtAppAddTimeOut, help John B. Matthews, M.D.
1999-05-30 0:00 ` Paul Hussein
1999-06-01 0:00 ` dennison
@ 1999-06-07 0:00 ` John
2 siblings, 0 replies; 4+ messages in thread
From: John @ 1999-06-07 0:00 UTC (permalink / raw)
Thanks to everyone who offered insight into this problem. Many pointed
out that XtAppContext wasn't being initialized; others observed that
there was no X event loop. The correct solution was a combination of
both. Specifically, the XtAppContext passed to XtAppAddTimeOut must be
precisely the same one created at initialization time and later used in
the event loop.
John
In article <matthewsj-ya023680003005990012190001@news.saic.com>,
matthewsj@deleteme.saic.com (John B. Matthews, M.D.) wrote:
> Under IRIX 6.5, I'm trying to set up a callback using the X-windows
> function Xt.Intrinsic.XtAppAddTimeOut. For some reason, the code
raises
> Program_Error when the call to XtAppAddTimeOut occurs. Example code
> follows. I've tried making my own binding and allocating more space to
> Xt.Intrinsic.XtAppStruct. The SGI binding appears to match the
declaration
> in Intrinsic.h. A call to the obsolete function XtAddTimeOut succeeds,
but
> the callback never excecutes. Any insights much appreciated; post or
email
> (sans deleteme) is fine.
>
> Thanks in advance,
>
> John
>
> ----- gnatchop here ----
> -- gnatmake -g -n32 -mips3 timeout.adb -largs -lXm -lXt -lMrm -lX11
> with Ada.Unchecked_Conversion;
> with System;
> with Text_IO;
> with Timer_CB;
> with Xt.Intrinsic;
>
> procedure TimeOut is
>
> --- Convert a System.Address to an XtPointer
> function To_XtPointer is new Ada.Unchecked_Conversion (
> System.Address, Xt.Intrinsic.XtPointer);
>
> --- Timer static data
> App_Context : Xt.Intrinsic.XtAppContext := new
Xt.Intrinsic.XtAppStruct;
> Timer_Id : Xt.Intrinsic.XtIntervalId := 0;
>
> begin
> --- Add a timer callback
> Timer_Id := Xt.Intrinsic.XtAppAddTimeOut ( -- dies here!
> App_Context => App_Context,
> Interval => 200, -- 200 msec
> Proc => Timer_CB.Timer_Callback'Access,
> Closure => To_XtPointer (Timer_Id'Address));
> Delay 10.0;
> Text_IO.Put_Line("Main ends.");
>
> end;
>
> package body Timer_CB is
>
> procedure Timer_Callback (
> Closure : Xt.Intrinsic.XtPointer;
> Id : access Xt.Intrinsic.XtIntervalId) is
> begin
> Text_IO.Put_Line("In callback.");
> end Timer_Callback;
>
> end;
>
> with Text_IO;
> with Xt.Intrinsic;
>
> package Timer_CB is
>
> procedure Timer_Callback (
> Closure : Xt.Intrinsic.XtPointer;
> Id : access Xt.Intrinsic.XtIntervalId);
> pragma Convention (C, Timer_Callback);
>
> end;
> ----- code ends -----
>
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^ permalink raw reply [flat|nested] 4+ messages in thread