RE: [cdt-debug-dev] Problem suspending Cygwin-based GDB from Ecli pse/CD

[Doug Schaefer <DSchaefer@xxxxxxx>]

Yes, CDT 3.1.2 will have trouble suspending newer cygwin-based gdb's. There
are more recent CDT 3.1.x builds where this has been fixed (by grabing the
spawner and starter from CDT 4.0 and bringing it back). Cygwin changed the
mechanism by which suspends work sometime last year.

The 3.1.2 builds are on the nightly build site.

  http://download.eclipse.org/tools/cdt/builds/3.1.2

Cheers,
Doug Schaefer, QNX Software Systems
Eclipse CDT Project Lead, http://cdtdoug.blogspot.com


> -----Original Message-----
> From: cdt-debug-dev-bounces@xxxxxxxxxxx [mailto:cdt-debug-dev-
> bounces@xxxxxxxxxxx] On Behalf Of Stefan Bylund
> Sent: Monday, December 03, 2007 10:23 AM
> To: cdt-debug-dev@xxxxxxxxxxx
> Subject: [cdt-debug-dev] Problem suspending Cygwin-based GDB from
> Eclipse/CDT (and some findings)
> 
> Hi,
> 
> I'm cross-posting this from the cygwin mailing list since I believe it
> can be of interest to other Eclipse/CDT developers and users.
> 
> 
> Message from cygwin mailing list:
> ---------------------------------
> 
> Hi,
> 
> We have a source code debug solution based on Eclipse / CDT / GDB / GCC
> / Cygwin DLL. We are using Eclipse 3.2.2 / CDT 3.1.2 / GDB 6.3 / GCC
> 3.4.4 / Cygwin DLL 1.5.19-4 (cygwin1.dll).
> 
> Until now, we have only supported Windows XP but recently we were forced
> to upgrade to a newer version of the cygwin1.dll (1.5.24-2) since we had
> to support Windows Vista, and Cygwin-based GCCs didn't work correctly
> with cygwin1.dll 1.5.19-4 on Windows Vista due to heap errors in
> cygwin1.dll. However, GDB works fine with cygwin1.dll 1.5.19-4 on
> Windows Vista.
> 
> Unfortunately, I just discovered that suspending GDB from Eclipse/CDT no
> longer works. So I tried all versions of the cygwin1.dll from 1.5.19-4
> to the forthcoming 1.5.25-3 and found that starting from version
> 1.5.20-1, the signal handling in cygwin1.dll seems to have changed in
> such a way that suspending GDB from Eclipse/CDT no longer works. Note
> that versions before 1.5.19-4 of the cygwin1.dll also works correct with
> respect to suspending GDB from Eclipse/CDT.
> 
> By searching the cygwin mailing list, it seems that it is a general
> problem when trying to programatically send a SIGINT from one process to
> another process.
> 
> I looked at the cygwin change list from 1.5.19-4 to 1.5.20-1
> (http://cygwin.com/ml/cygwin-announce/2006-07/msg00000.html) and noticed
> the following signal-related changes:
> 
> * cgf: When sending signals, assume that any code which is not directly
> associated with a DLL or an executable is user code.
> 
> * cgf: Pass cygwin signals to gdb. Fix the dreaded SIGSEGV found in some
> pthread functions.
> 
> * corinna: Implement sigignore and sigset.
> 
> * cgf: Make SA_RESTART sigaction flag work more like linux.
> 
> It seems that one or more of the changes listed above (or some other
> change(s) described in
> http://cygwin.com/ml/cygwin-announce/2006-07/msg00000.html) is the cause
> of this problem. It is a bit ironic that one of the changes mentions
> passing cygwin signals to gdb since it is exactly this functionality
> that is now broken but, from our experience, worked in 1.5.19-4.
> 
> I'm cross posting this mail to the CDT mailing list as well, since there
> may be other Eclipse/CDT users interested in this issue.
> 
> Is there anything I can do to help in finding out why versions starting
> from 1.5.20-1 of the cygwin1.dll no longer supports programatically
> sending a SIGINT from one process to another? If nothing else, I can at
> least help out with testing.
> 
> 
> Best Regards,
> Stefan Bylund
> 
> 
> --
> ---------------------------------
> Stefan Bylund
> Senior Software Engineer
> Enea
> Skalholtsgatan 9,
> Box 1033, SE-164 21 Kista, Sweden
> Direct: +46 8 50 71 43 25
> Mobile: +46 709 71 43 25
> stefan.bylund@xxxxxxxx
> www.enea.com
> ---------------------------------
> Enea - Embedded for Leaders
> ---------------------------------
> 
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