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Re: pthreads VCE: problem with destructor

On Wed, 19 Dec 2001, reentrant wrote:

> Due to the nature of the beast just as the responsibility lies with the
> programmer to design the program to "cleanly" (including running
> destructors,
> ad nauseum) exit when exit() is called, it should also be the
> responsibility of
> the programmer to design a thread to cleanly exit with pthread_exit() or
> pthread_cancel() are called.  Just as exit() should not be called in a
> C++
> program if dtors are desired to run neither should pthread_exit() from a
> thread.  IMHO.
> I would imagine that exit() was chosen not to be modified to account for
> running C++ destructors for about the same reasons that pthread_exit()
> should
> not account for running C++ destructors.  Dtors not being called in
> these cases
> is and should be expected behavior.
> Regardless as Mr. Bossom so well has already stated: I certainly
> wouldn't
> depend on pthread_exit() or pthread_cancel() allowing destructors to run
> to be
> portable though.  Since the primary purpose of this library is to
> enhance
> portability of programs using pthreads, counting on pthread_exit() or
> pthread_cancel() to work in a non-portable way seems self-defeating.

This is exactly the reason why i have created the setjmp/longjmp version.
There may be bugs in it but i think they could be discovered if more would
using it.

> While attempting to allow dtors to be run upon a pthread_exit() or
> pthread_cancel() is certainly a noble goal, it's beyond the scope of the
> pthread library.  It's the programmer's responsibility IMHO.
> So, as I hope is obvious by this point :), I am completely in support of
> the
> "nasty hacks" being removed and a clean C interface version of the
> library
> being provided only.

Try the GC stuff and report bugs.

> My two cents,
> Dave
> --- Ross Johnson <> wrote:
> > I sense a rising and ruthless desire to deal with the problem of
> > the exception-based versions of the library. It would certainly
> > be a lot easier if they weren't there, and there are some
> > hacks in pthread.h supporting them that really are nasty.
> >
> > So ... what to do about them?
> >
> > I will firstly put John's warning in the README file
> > and the README.NONPORTABLE file, and on the Web page.
> >
> > Secondly, there is a standard C version of the library courtesy
> > of Thomas Pfaff's contributions. It uses setjmp/longjmp.
> > Does this need to be built differently to work with C++
> > applications (assuming they are written as John suggests they
> > should be)?

No. The only thing you need is to define __CLEANUP_C to avoid the default
handling in pthread.h.

 * define defaults for cleanup code
#if !defined( __CLEANUP_SEH ) && !defined( __CLEANUP_CXX ) && !defined(

#if defined(_MSC_VER)
#define __CLEANUP_SEH
#elif defined(__cplusplus)
#define __CLEANUP_CXX
#define __CLEANUP_C


These defaults have been added to be backward compatible and it is time to
remove them.

> > I can try putting it through the VCE run of the
> > test suite as soon as I reinstall my corrupted Windows 98 machine.
> >
> > Thirdly, if possible, consider phasing out all but the VC and GC
> > versions of the library (currently the only standard C versions).
> > That is, phase out the VCE, VSE, and GCE versions.
> >
> > Does anyone wan't to jump up and shout - NO!!
> >
> > Ross
> >


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