motif text widgets

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2 total messages Started by LANGER STEVEN C Wed, 13 Jan 1993 04:09

#107

Author: LANGER STEVEN C
Date: Wed, 13 Jan 1993 04:09

66 lines
2478 bytes

Hi folks;
  Another question, this time on text widgets. I have a dialog with
several one line text widgets attached to it. To the right of each
text widget is a button. When the button is pressed, I want new text to show
up in the assocaited text widget.

________________________________________________
|
| text1 b1
| 
| text2 b2
|
|

the code fragment is
{
	dialog = XmCreateDialogShell (toplevel, ...

	form = XmCreateForm (dialog, ...

	text1 = XmCreateTextWidget (form, attach upper left
	b1  = XmCreatePushButton (form, attach to right of text widget

	XtAddCallback (b1, XmNactivateCallback, cbfunc, "b1");
	XtManageChild (form);
	XtManageChild (dialog);
}

void cbfunc (Widget w, XtPointer data, XtPointer dummy)
{
	char *text;
	char str[]="here i am";

	if (strcasecmp(data, "b1") == 0)
	{
		temp = XtMalloc (sizeof(str));
		temp[sizeof(str)] = 0	;	/* null terminator */
		XmTextSetString (w, text);
		XtFree (text);
	}

}

This is my adaptation of Heller's example 15-2 file browser.c
program. The cbfunc is based on read_file.


The dialog is created and the default text is drawn, but when the b1
is pressed, I get a core dump and dbx zeros in on the
XmTextSetString call.

Any ideas on how to beat this?

--thanks in advance, steve

-- 
Steve Langer  			       sglanger@argo.acs.oakland.edu (VMS)
Oakland University		       sglanger@vela.acs.oakland.edu (Ultrix)
---------------------------------------------------------------------------
Standard disclaimers apply. In addition, the author makes no guarantees,
concerning the grammatical accuracy of his writing. Therefore, any ^B's, ^C's, 
midword character additions/deletions and other non-sense which occurs (after 
the work leaves the author's decade old text editor via his decade old Amiga, 
struggles through a local 1200 baud Merit server to be further mauled via the 
remote VAX mail servers) is someone elses problem - namely yours.
---------------------------------------------------------------------------

Re: motif text widgets

#108

Author: Mike Yang
Date: Wed, 13 Jan 1993 04:33

32 lines
1295 bytes

In article <1993Jan13.040941.4854@vela.acs.oakland.edu> sglanger@vela.acs.oakland.edu (LANGER STEVEN C) writes:
>void cbfunc (Widget w, XtPointer data, XtPointer dummy)
>{
>	char *text;
>	char str[]="here i am";
>
>	if (strcasecmp(data, "b1") == 0)
>	{
>		temp = XtMalloc (sizeof(str));
>		temp[sizeof(str)] = 0	;	/* null terminator */
>		XmTextSetString (w, text);
>		XtFree (text);
>	}
>
>}

The variable text is uninitialized.  Did you want to say:

	XmTextSetString (w, temp);

instead?

Also, your null terminator is past the bounds of the array you allocate.
You probably want:

	temp[sizeof(str)-1] = '\0';

instead.

-----------------------------------------------------------------------
                 Mike Yang        Silicon Graphics, Inc.
               mikey@sgi.com           415/390-1786

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