[M3devel] Problem interfacing C lib

[Daniel Alejandro Benavides D.]

Hi all:
I think the unchecked error lays down to:
Unsafe Operations section 2.7 (cf. Green Book SPWM3, p- 61):
it's allowed to have " ... a value of type ADDRESS to be assigned to a variable of type UNTRACED REF T. It is an unchecked runtime error if the value does not address a variable of type T."

which could be reads conversely as:

a value of type UNTRACED REF T to be assigned to a variable of type ADDRESS. It is a checked runtime error if the variable does not address      a variable of type .T 
 
And because because char_star is a subrange [-128 .. 127] OF INTEGER (and not ADDRESS)  and chars is UNTRACED REF ARRAY OF CHAR erro is cf. the specification.
So maybe you need to change your char_star

Thanks in advance


--- El mar, 20/3/12, Dragiša Durić <dragisha at m3w.org> escribió:

> De: Dragiša Durić <dragisha at m3w.org>
> Asunto: Re: [M3devel] Problem interfacing C lib
> Para: "Mika Nystrom" <mika at async.caltech.edu>
> CC: m3devel at elegosoft.com
> Fecha: martes, 20 de marzo, 2012 01:04
> Errorr is SIGSEGV.
> 
> chars is UNTRACED REF ARRAY OF CHAR but it is lesser
> problem, I think. It looks like  formal 'what' is not
> sent at all!? It's place is taken by next argument - INTEGER
> len (equal 0x7 in this example).
> 
> One common problem I meet often (as I bind C often :) is
> this - address of open array argument is ot what it looks
> like. To be sure you are getting address of various UNTRACED
> REF..ARRAY.. and open array procedure arguments - use 
> 
> ADR(chars[0])
> 
> and do not use:
> 
> LOOPHOLE(chars, ADDRESS)
> 
> Of course, I tried ADR(chars[0]) :) - Same thing happened.
> Right now II downgraded my code to use strstr(3), but this
> argument passing still bugs me.
> 
> dd
> 
> 
> On Mar 20, 2012, at 1:26 AM, Mika Nystrom wrote:
> 
> > What are the declarations of all the variables involved
> in the call?
> > 
> > And what is the actual error?  Is it a SIGBUS,
> SIGSEGV?
> > 
> > =?utf-8?Q?Dragi=C5=A1a_Duri=C4=87?= writes:
> >> I had some error before I LOOPHOLEd it.
> >> 
> >> On Mar 19, 2012, at 7:27 PM, Daniel Alejandro
> Benavides D. wrote:
> >> 
> >>> Hi all:
> >>> if chars is ADDRESS type why are you
> LOOPHOLE'ing it?=20
> >>> Thanks in advance
> >>> =20
> >>> --- El lun, 19/3/12, Dragi=C5=A1a Duri=C4=87
> <dragisha at m3w.org>
> =
> >> escribi=C3=B3:
> >>> =20
> >>>> De: Dragi=C5=A1a Duri=C4=87 <dragisha at m3w.org>
> >>>> Asunto: [M3devel] Problem interfacing C
> lib
> >>>> Para: "m3devel" <m3devel at elegosoft.com>
> >>>> Fecha: lunes, 19 de marzo, 2012 12:13
> >>>> #1  0x00000035bd8172a0 in
> >>>> evbuffer_search_range (buffer=3D0x694090,
> what=3D0x7 <Address
> >>>> 0x7 out of bounds>, len=3D0,
> start=3D0x0,
> >>>> end=3D0x7fffffffdbb0)
> >>>>   at buffer.c:2441
> >>>> #2  0x0000000000404a0c in
> Buffer__Search (t=3D<error
> >>>> reading variable>, pattern=3D<error
> reading
> >>>> variable>, from=3D<error reading
> variable>,=20
> >>>>   to=3D<error reading
> variable>) at
> >>>> ../src/Buffer.m3:150
> >>>> =20
> >>>> Buffer.m3:150
> >>>>       pos :=3D
> >>>> evbuffer.search_range(t.b, LOOPHOLE(chars,
> ADDRESS), len,
> >>>> NIL, NIL);
> >>>> =20
> >>>> t.b is a pointer, so is chars=E2=80=A6 len
> is Utypes.size_t and
> >>>> it's value is 7.
> >>>> =20
> >>>> <* EXTERNAL evbuffer_search_range *>
> >>>> PROCEDURE search_range(buf: t; what:
> char_star; len: size_t;
> >>>> start, end: UNTRACED REF ptr): ptr;
> >>>> =20
> >>>> t is an ADDRESS, and so on=E2=80=A6
> >>>> =20
> >>>> Critical Mass Modula-3 version d5.9.0
> >>>> last updated: 2010-07-21
> >>>> compiled: 2010-10-04 07:24:16
> >>>> configuration: /etc/cm3.cfg
> >>>> host: AMD64_LINUX
> >>>> target: AMD64_LINUX
> >>>> =20
> >>>> =20
> >>>> Any ideas? TIA,
> >>>> dd
> >>>> =20
> >>>> =20
> 
>