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From: dewar@merv.cs.nyu.edu (Robert Dewar)
Subject: Re: Reading a line of arbitrary length
Date: 1997/03/06
Message-ID: <dewar.857651874@merv>#1/1
X-Deja-AN: 223528447
References: <dewar.857447653@merv> <5fh7hp$l3c@mulga.cs.mu.OZ.AU>
 <5fijee$51j$1@goanna.cs.rmit.edu.au> <5flmbc$nkm@mulga.cs.mu.OZ.AU>
Organization: New York University
Newsgroups: comp.lang.ada
Date: 1997-03-06T00:00:00+00:00
List-Id: <comp.lang.ada>


iFergus says

<<So how transparent is the GC when used with the foreign language
interface?  Can one pass a pointer to a dynamically allocated SNOBOL4
data structure to the C code?  What happens if the last pointer to such
a data structure exists only in a C global variable?
>>

Given that typical SNOBOL4 compilers have compacting collectors, they
are WAY out of range of this kind of consideration. A conservative
collector cannot conservatively modify things that it is not sure are
pointers! So the answer is that C can reference structures, but cannot
hold onto pointers AT ALL, let alone be the only one to hold on to them!