RE: C++ exceptions don't work from Cygwin DLLs?

[Robert Collins]

Danny, I hope you don't object to being copied in...

> -----Original Message-----
> From: Charles Wilson [mailto:address@hidden 
> Sent: Saturday, May 11, 2002 7:49 AM
> To: Bob Friesenhahn
> Cc: address@hidden; Robert Collins
> Subject: Re: C++ exceptions don't work from Cygwin DLLs?
> 
> 
> Bob Friesenhahn wrote:
> 
> > I am attempting to get ImageMagick to work properly using 
> Cygwin DLLs. 
> > The C++ component is built as a DLL using the binutils auto-import 
> > feature and CVS libtool.  The library works fine with the glaring 
> > exception that any C++ exception thrown from the library causes an 
> > immediate core dump.  I have verified that C++ exceptions 
> do work if 
> > they are not thrown from a DLL, and the library passes all tests 
> > (including C++ exceptions) if it is built as a static library.
> > 
> > Do you believe that C++ exceptions should be working with 
> Cygwin DLLs?
> 
> 
> No, not yet.  I don't know a whole lot about this, but I 
> think that we 
> need to have a gcc and libg++ that supports threads; and we 
> don't have 
> that yet.  But that is supposedly a high priority.  I think. I'm 
> forwarding this message to Robert Collins; he may be able to 
> clariy my 
> confusion.
> 
> Robert -- what's the deal with C++ and exceptions under cygwin, again?

Single thread C++ programs should work fine. Exceptions from .dll's
-may- be problematic. Danny knows more about this aspect than I do. He
posted a summary message about gcc 3-something at one point that listed
c++ exceptions and .dll's as an issue.

As for multi-threaded C++ exceptions, they will sporadically fail unless
a custom build gcc and libstdc++ and libgcc are used that has been build
with --with-threads or --with-threads=posix or --with-threads=win32.

Rob.