RE: [EXT] Re: XWin copy/paste succeeds on Windows 7, crashes on Windows 11 Enterprise.

["Stone, Timothy M" <tstone@ida.org>]

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I've finally figured out what was happening here.

The issue was not related to Cygwin.


For those interested:

I compile my app using libraries from Exceed, then later use Cygwin as my X Server.

I had (2) problems here:
(1) I was using the wrong version of the Exceed DLLs at runtime.
(2) There appears to be a bug in Exceed 15 where if you set the environment variable "UserDir", it causes the cut/paste functionality to not work.  There was a previous bug where NOT setting this variable caused other issues.

thanks for all your help!




From: Stone, Timothy M
Sent: Wednesday, November 8, 2023 10:24 AM
To: 'cygwin@cygwin.com' <cygwin@cygwin.com>
Subject: RE: [EXT] Re: XWin copy/paste succeeds on Windows 7, crashes on Windows 11 Enterprise.


I have made an important discovery here.  I've been using "release" mode when compiling, and had the following results:


On Windows 11 enterprise (release):

When using "translations_ignore", it correctly just prints "Ignoring" every time I cut/copy/paste.

When using "translations_copypaste", the program crashes.



On Windows 7 professional (release):

When using "translations_ignore", it correctly just prints "Ignoring" every time I cut/copy/paste.

When using "translations_copypaste", it correctly cuts/copies/pastes.


I have now compiled and run the program in "debug" mode and have noticed an important difference.

Instead of crashing on Windows 11 when trying to copy/paste, the program prints an error message and actually exits.

The error message is:
"Error: Error - registered format name must be nonnull"

Does anyone know where this error message is coming from?

I am starting to suspect that Windows clipboard integration routines have changed since Windows 7 and are not being used correctly internally.
I see there are some functions (which I presume are used internally) that sound a lot like this error message.
"RegisterClipboardFormat()" and "GetClipboardFormatName()", for instance.


Hopefully this new information can help the experts help me determine why my program is working on Windows 7 and crashing on Windows 11.

thanks!



From: Stone, Timothy M
Sent: Tuesday, November 7, 2023 12:21 PM
To: cygwin@cygwin.com
Subject: RE: [EXT] Re: XWin copy/paste succeeds on Windows 7, crashes on Windows 11 Enterprise.




I have created an entire program to test this.  It's only 40 lines.  The program pops up a type in window...then you can type something in it and test the copy/paste.



On Windows 11 enterprise:

When using "translations_ignore", it correctly just prints "Ignoring" every time I cut/copy/paste.

When using "translations_copypaste", the program crashes.



On Windows 7 professional:

When using "translations_ignore", it correctly just prints "Ignoring" every time I cut/copy/paste.

When using "translations_copypaste", it correctly cuts/copies/pastes.



Of course, you'll need to link with X/Motif libraries, and possibly change the one line to point at your XKeysymDB, but this 40 line program shows the whole problem:




#include <stdio.h>
#include <stdlib.h>
#include <Xm/RowColumn.h>
#include <Xm/TextF.h>

void ignore_cut_paste(Widget widget, XEvent *event, String *args, int *num_args)
{
  printf("Ignoring\n");
}

int main(int argc, char **argv)
{
  Widget W,thewin,rowcol,textarea;
  XtAppContext app_context;
  XtActionsRec actions2;

  _putenv("display=127.0.0.1:0.0");
  _putenv("xkeysymdb=.\\XKeysymDB");

  W = XtAppInitialize(&app_context, (String)"Test",NULL,(Cardinal)0,&argc,argv,NULL,NULL,(Cardinal)0);

  actions2.string = "ignore_cut_paste";
  actions2.proc = (XtActionProc)ignore_cut_paste;
  XtAppAddActions (app_context, &actions2, 1);

  String translations_copypaste = "#override\n Ctrl<Key>v:  paste-clipboard()\n Ctrl<Key>c:  copy-clipboard()\n Ctrl<Key>x:  cut-clipboard()";
  String translations_ignore = "#override\n Ctrl<Key>v:  ignore_cut_paste()\n Ctrl<Key>c:  ignore_cut_paste()\n Ctrl<Key>x:  ignore_cut_paste()";

  thewin = XtCreatePopupShell("Test", topLevelShellWidgetClass,W,NULL,0);
  rowcol = XtVaCreateWidget ("rowcol",xmRowColumnWidgetClass, thewin, NULL);
  textarea = XtVaCreateManagedWidget ("test_area",
                                  xmTextFieldWidgetClass, rowcol,
                                  XmNmaxLength,        80,
                                  XmNtranslations,     XtParseTranslationTable ( translations_copypaste ) ,
                                  NULL);
  XtManageChild(textarea);
  XtManageChild (rowcol);
  XtPopup(thewin,XtGrabNone);
  XtAppMainLoop(app_context);
}