Re: -dgui option dropped in 2.24 - how to stop the black box on Windows now?

[Jean Abou Samra]

Le mardi 04 avril 2023 à 11:34 +0200, Jean Abou Samra a écrit :

Le lundi 03 avril 2023 à 20:50 +0200, Jonas Hahnfeld via LilyPond user discussion a écrit :

This shouldn't be needed: g_spawn_sync internally uses a helper
executable that should take care exactly of this aspect. LilyPond uses
it internally to call Ghostscript.

Hmm, but Denemo is already using g_spawn_sync and still experiencing this issue, or am I missing something?

You are right that the GLib sources contain a gspawn-win32-helper.c program with the comment

/* We build gspawn-win32-helper.exe as a Windows GUI application
 * to avoid any temporarily flashing console windows in case
 * the gspawn function is invoked by a GUI program. Thus, no main()
 * but a WinMain().
 */

Later, there is

#ifndef HELPER_CONSOLE
int _stdcall
WinMain (struct HINSTANCE__ *hInstance,
	 struct HINSTANCE__ *hPrevInstance,
	 char               *lpszCmdLine,
	 int                 nCmdShow)
#else
int
main (int ignored_argc, char **ignored_argv)
#endif

Apparently, there are two such executables, gspawn-win32-helper.exe and gspawn-win32-helper-console.exe, the latter compiled with -DHELP_CONSOLE.

In gspawn-win32.c, I see

  if (might_be_console_process ())
    helper_process = HELPER_PROCESS "-console.exe";
  else
    helper_process = HELPER_PROCESS ".exe";

which calls

static gboolean
might_be_console_process (void)
{
  // we should always fail to attach ourself to a console (because we're
  // either already attached, or we do not have a console)
  gboolean attached_to_self = AttachConsole (GetCurrentProcessId ());
  g_return_val_if_fail (!attached_to_self, TRUE);

  switch (GetLastError ())
    {
    // current process is already attached to a console
    case ERROR_ACCESS_DENIED:
      return TRUE;
    // current process does not have a console
    case ERROR_INVALID_HANDLE:
      return FALSE;
    // we should not get ERROR_INVALID_PARAMETER
    }

  g_return_val_if_reached (FALSE);
}

Richard, maybe might_be_console_process is returning true inside Denemo for some reason?

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