Re: [tpfaff@cygwin.com: src/winsup/cygwin ChangeLog thread.cc thread.h]

[Thomas Pfaff <tpfaff at gmx dot net>]

Corinna Vinschen wrote:
> ----- Forwarded message from tpfaff@cygwin.com -----
>
> > Date: 1 Dec 2003 22:10:57 -0000
> > From: tpfaff@cygwin.com
> > Subject: src/winsup/cygwin ChangeLog thread.cc thread.h
> > To: cygwin-cvs@cygwin.com
> >
> > CVSROOT:	/cvs/src
> > Module name:	src
> > Changes by:	tpfaff@sourceware.org	2003-12-01 22:10:57
> >
> > Modified files:
> > 	winsup/cygwin  : ChangeLog thread.cc thread.h 
> >
> > Log message:
> > 	* thread.cc (pthread_rwlock::add_reader): Remove mx parameter for
> > 	List_insert call.
> > 	(pthread::prepare): Ensure race safeness when adding function
> > 	pointers to atfork lists by using List_insert.
> > 	* thread.h (List_insert): Use InterlockedCompareExchangePointer to
> > 	ensure race safeness without using a mutex.
> > 	(List_remove): Use InterlockedCompareExchangePointer to
> > 	ensure race safeness with List_insert.
> > 	(List::insert): Remove mx parameter for	List_insert call.
> >
> > Patches:
> > http://sources.redhat.com/cgi-bin/cvsweb.cgi/src/winsup/cygwin/ChangeLog.diff?cvsroot=src&r1=1.2201&r2=1.2202
> > http://sources.redhat.com/cgi-bin/cvsweb.cgi/src/winsup/cygwin/thread.cc.diff?cvsroot=src&r1=1.148&r2=1.149
> > http://sources.redhat.com/cgi-bin/cvsweb.cgi/src/winsup/cygwin/thread.h.diff?cvsroot=src&r1=1.78&r2=1.79
>
>
> ----- End forwarded message -----
>
> Doesn't this patch result in not being able to run Cygwin on Win 95
> anymore?  InterlockedCompareExchangePointer is only available since
> 98 according to MSDN.  Or did we leave 95 already behind somewhere
> on the way?

Not at all.

The whole interlocked stuff is inline assembled in winbase.h .
The only thing that is lost some time ago is the good old i386 (since it 
has no xadd/cmpxchg instructions).

Thomas

P.S.: The mutex code is using InterlockedCompareExchange over one year 
now and nobody complained, but i am still waiting for the one who is 
using cygwin on an i386.