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Re: [Patch] Loading cygwin1.dll from MinGW and MSVC


I fat fingered my response to Max, ended up sending a personal message
and never noticed until I received a personal reply from him.  I, of
course, asked him not to send me personal email which was pretty
confusing since I'd previously just sent him a personal reply.

Translation:  I am a maroon.

Anywhay this is what should have gone out days ago.

On Fri, Jun 03, 2005 at 03:58:09PM -0700, Max Kaehn wrote:
>This patch contains the changes to make it possible to dynamically load
>cygwin1.dll from MinGW and MSVC applications.  The changes to dcrt0.cc are
>minimal and only affect cygwin_dll_init().  I've also added a MinGW test
>program to testsuite and a FAQ so people will be able to locate the
>test program easily.
>
>I wrote how-cygtls-works.txt because it took me a while to figure out how it
>was storing the information, and I hope I can save someone else the effort in
>the future.  (I had no idea Windows was still using segment registers!)
>I hope I got the copyright message right for it.

Wow! That's great! Thanks for doing this.  It is much appreciated.  This
is something that I had been meaning to do and you did a better job than
I would have.  This truly deserves a gold star.  I know that understanding
the cygtls stuff could not have been easy.

Can I get a gold star over here for this truly heroic effort?

I have checked in everything but the test suite stuff.  I would like to
see some changes there:

1) Use '.cc' rather than '.cpp' for the extension to be consistent with
the rest of winsup.

2) Use the same formatting that is used throughout cygwin for brace
placement, etc.

3) Submit the new files as diffs against /dev/null so that I can apply
like a normal patch.

Did you consider other ways of dealing with the need for space at the
bottom of the stack?

Having an interface which requires a "main" function name so that you'd
do something like:

int
main (int argc, char **argv)
{
  initialize_cygwin (rest_of_main, argc, argv);
  /* never returns */
}

int
rest_of_main (argc, argv)
{
  /* do main stuff */
  .
  .
  .
  exit or return here
}

And in cygwin initialize_cygwin would look something like:

void
initialize_cygwin (int (*) main, int argc, char **argv)
{
  struct _cygtls dummy_tls;
  initialize_main_tls (&dummy_tls);  
  cygwin_dll_init ();
  exit (main (argc, argv));
}

And declaring initialize_cygwin as a "__attribute__ ((noreturn))" in an
appropriate header file.

This has the downside of maybe causing more code disruption, though...

cgf


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