[M3devel] Modula-3/C interop in Date/Time?

Fri Apr 16 16:30:48 CEST 2010

What is the use-case here?

Merely having UNTRACED references doesn't make your code unsafe.  Using ADR does.

But why not have an interface with C that makes use of the fact that VAR parameters are passed as pointers to C.

e.g., C function

f(int *ref p)

can be declared as

<*EXTERNAL*> f(VAR i: INTEGER)

and this is still safe.

On 16 Apr 2010, at 04:18, Jay K wrote:

> Isn't making them unsafe? ADR? I'll try..
> 
> - Jay
> 
> > To: jay.krell at cornell.edu
> > Date: Fri, 16 Apr 2010 00:00:34 -0700
> > From: mika at async.async.caltech.edu
> > CC: m3devel at elegosoft.com
> > Subject: Re: [M3devel] Modula-3/C interop in Date/Time?
> > 
> > I don't think there's anything unsafe about UNTRACED.
> > 
> > It's DISPOSE that's unsafe...
> > 
> > Mika
> > 
> > Jay K writes:
> > >--_cbaca81c-f322-4f31-8684-e7f171e67f3d_
> > >Content-Type: text/plain; charset="iso-2022-jp"
> > >Content-Transfer-Encoding: 7bit
> > >
> > >But then unsafe, right?
> > >
> > > - Jay
> > >
> > >> From: hosking at cs.purdue.edu
> > >> Date: Thu, 15 Apr 2010 22:06:14 -0400
> > >> To: rodney_bates at lcwb.coop
> > >> CC: m3dev el at elegosoft.com
> > >> Subject: Re: [M3devel] Modula-3/C interop in Date/Time?
> > >> 
> > >> Indeed! UNTRACED.
> > >> 
> > >> 
> > >> On 15 Apr 2010, at 18:44, Rodney M. Bates wrote:
> > >> 
> > >> > Since these pointer variables are initialized by
> > >> > C code and their referents are also provided by C code
> > >> > as global variables, shouldn't the type be untraced?
> > >> > 
> > >> > I suppose that, since they don't point into the traced
> > >> > heap, the collector implementation we have would quietly
> > >> > ignore them as roots. But that's relying on implementation-
> > >> > dependent information.
> > >> > 
> > >> > Also, if someone created a field of type Date.TimeZone,
> > >> > (or an array of them) in a traced-heap-allocated object,
> > > > which is a perfectly legitimate thing to do, what would
> > >> > our collector do then?
> > >> > 
> > >> > 
> > >> > 
> > >> > Jay K wrote:
> > >> >> Is this legal/correct?
> > >> >> 
> > >> >> 
> > >> >> Date.i3:
> > >> >> TYPE TimeZone <: REFANY;
> > >> >> VAR Local, UTC: TimeZone; (* granted, will maybe change these to extern *)
> > >> >> 
> > >> >> 
> > >> >> Date.m3:　
> > >> >> REVEAL TimeZone = BRANDED "Date.TimeZone" REF INTEGER;
> > >> >> 　
> > >> >> 
> > >> >> DatePosixC.c:
> > >> >> static const int Local = 0& #59;
> > >> >> static const int UTC = 1;
> > >> >> extern const int const * const Date__Local = &Local;
> > >> >> extern const int const * const Date__UTC = &UTC;
> > >> >> 　
> > >> >> 
> > >> >> - Jay
> > >> 
> > > 
> > >--_cbaca81c-f322-4f31-8684-e7f171e67f3d_
> > >Content-Type: text/html; charset="iso-2022-jp"
> > >Content-Transfer-Encoding: 7bit
> > >
> > ><html>
> > ><head>
> > ><style><!--
> > >.hmmessage P
> > >{
> > >margin:0px;
> > >padding:0px
> > >}
> > >body.hmmessage
> > >{
> > >font-size: 10pt;
> > >font-family:Verdana
> > >}
> > >--></style>
> > ></head 2;
> > ><body class='hmmessage'>But then unsafe, right?<br><br> - Jay<br><br>> From: hosking@cs.purdue.edu<br>> Date: Thu, 15 Apr 2010 22:06:14 -0400<br>> To: rodney_bates&
> > >#64;lcwb.coop<br>> CC: m3devel@elegosoft.com<br>> Subject: Re: [M3devel] Modula-3/C interop in Date/Time?<br>> <br>> Indeed! UNTRACED.<br>> <br>> <
> > >br>> On 15 Apr 2010, at 18:44, Rodney M. Bates wrote:<br>> <br>> > Since these pointer variables are initialized by<br>> & #38;#62; C code and their referents are also provided by C
> > > code<br>> > as global variables, shouldn't the type be untraced?<br>> > <br>> > I suppose that, since they don't point into the traced<br>> > heap, the collect
> > >or implementation we have would quietly<br>> > ignore them as roots. But that's relying on implementation-<br>> > dependent information.<br>> > <br>> > Also, if someon
> > >e created a field of type Date.TimeZone,<br>> &#62
> > > ; (or an array of them) in a traced-heap-allocated object,<br>> > which is a perfectly legitimate thing to do, what would<br >> > our collector do then?<br>> > <br>
> > >> > <br>> > <br>> > Jay K wrote:<br>> >> Is this legal/correct?<br>> >> <br>> >> <br>> >> Date.i3:<br>> >> TYPE TimeZone
> > > <: REFANY;<br>> >> VAR Local, UTC: TimeZone; (* granted, will maybe change these to extern *)<br>> >> <br>> >&# 38;#62; <br>> >>
> > > Date.m3:　<br>> >> REVEAL TimeZone = BRANDED "Date.TimeZone" REF INTEGER;<br>> >> 　<br>> >> <br>> >> DatePosixC.c:<br>
> > >> >> static const int Local = 0;<br>> >> static const int UTC = 1;<br>> >> extern const int const * const Date__Local = &Local;<br>>
> > > >> extern const int con st * const Dat
> > > e__UTC = &UTC;<br>> >> 　<br>> >> <br>> >> - Jay<br>> <br> </body>
> > ></html>
> > >--_cbaca81c-f322-4f31-8684-e7f171e67f3d_--

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