[M3devel] Downsides of Modula-3 ?

[Mika Nystrom]

But the thing is, if the produced code were thread unsafe, it likely
wouldn't work with user threads either...

I admit what you say is possible but it ought to be ruled out by the
semantics of pthreads.  

    Mika

"Daniel Alejandro Benavides D." writes:
>Hi all:
>Please this makes think that the current systems are a lottery, because the=
>y don't mark thread-safe code (or they are all safe assumed as thread-unsaf=
>e):
>http://h71000.www7.hp.com/doc/72final/6493/6101pro_008.html#making_safe
>
>Even if they compiler is not threaded by itself it can cause a back-end to =
>be thread-unsafe, so that's why I say that it could be in that back-end.
>
>But then the code must be marked by each module and I think assuming all ar=
>e thread-unsafe is correct to say.
>Thanks in advance
>
>--- El dom, 22/4/12, Mika Nystrom <mika at async.caltech.edu> escribi=F3:
>
>> De: Mika Nystrom <mika at async.caltech.edu>
>> Asunto: Re: [M3devel] Downsides of Modula-3 ?
>> Para: "Daniel Alejandro Benavides D." <dabenavidesd at yahoo.es>
>> CC: m3devel at elegosoft.com
>> Fecha: domingo, 22 de abril, 2012 12:30
>>=20
>> I'm almost certain the problem is somewhere in the pthreads
>> implementation
>> of M3 threads, which consists of a couple of files of C and
>> M3 within
>> m3core.
>>=20
>>     Mika
>>=20
>> "Daniel Alejandro Benavides D." writes:
>> >Hi all:
>> >I'm more suspicious about the back needs over this
>> programs, since Win32 pr=3D
>> >ograms have worked OK, have they? So I agree with you
>> it's a matter of targ=3D
>> >et implementation (not UNSAFE world), but that's in
>> m3gcc backend, isn't it=3D
>> >?
>> >Similarly your code could be fixed to uniprocessor
>> semantics, so if this te=3D
>> >sts are OK either pthreads or embedded M3 threads this
>> is a clear symptom o=3D
>> >f that UP semantics issue.
>> >In any case don't expect too many threads to do that
>> correctly, since any e=3D
>> >xception in them can't be managed by Modula-3 RT (by
>> language definition) b=3D
>> >ut at most in m3gcc semantics I believe so. DECthreads
>> had a nice mechanism=3D
>> > to wrap it to Modula-3 style semantics so it could be
>> easier to offer that=3D
>> > in a internal CM3 API.
>> >Thanks in advance
>> >
>> >
>> >--- El s=3DE1b, 21/4/12, Mika Nystrom <mika at async.caltech.edu>
>> escribi=3DF3:
>> >
>> >> De: Mika Nystrom <mika at async.caltech.edu>
>> >> Asunto: Re: [M3devel] Downsides of Modula-3 ?
>> >> Para: "Jay K" <jay.krell at cornell.edu>
>> >> CC: m3devel at elegosoft.com
>> >> Fecha: s=3DE1bado, 21 de abril, 2012 18:36
>> >> Jay K writes:
>> >> >1) please elaborate=3D20
>> >>=3D20
>> >> >2) We don't use longjmp as much any more=3D3D2C
>> but
>> >> get/set=3D3D
>> >> >/make/swapcontext on platforms that support
>> them.And
>> >> where we do use longjm=3D3D
>> >> >p=3D3D2C we have a more portable use than before
>> -- we no
>> >> longer hack on the jm=3D3D
>> >> >pbuf.There is a "trick" where you use
>> sigsetstack or
>> >> some such to get the s=3D3D
>> >> >tack pointer into the jmpbuf.Look at the code
>> and read
>> >> the paper referenced=3D3D
>> >> >. It is possible it didn't work on all
>> platforms.=3D20
>> >> But anyway=3D3D2C see #1.We'=3D3D
>> >> >d really prefer to just use pthreads.Hm. I'd
>> like to
>> >> look again at what pth=3D3D
>> >> >reads features we use -- I suspect
>> pthreads/Win32 can
>> >> beabstracted more thi=3D3D
>> >> >nly and the Modula-3 code
>> less-forked/more-shared. But
>> >> later..  - Jay > Fro=3D3D
>> >>=3D20
>> >> Sorry for the bad quote.  My mailer still
>> lives in the
>> >> 7-bit world.
>> >>=3D20
>> >> In any case I was just mentioning as a problem with
>> the
>> >> current Modula-3
>> >> implementation that the pthreads bindings are
>> buggy.  I
>> >> would not (and
>> >> do not) use them for serious work.  And user
>> threads
>> >> are, as we all know,
>> >> not ideal...
>> >>=3D20
>> >> Anybody who wants to investigate the matter can
>> start by
>> >> running the thread
>> >> testing program in m3core/tests/thread ...=20
>> Main.m3 is
>> >> fairly well documented.
>> >>=3D20
>> >>      Mika
>> >>=20
>>