Re: Reading a line of arbitrary length

[fjh@mundook.cs.mu.OZ.AU (Fergus Henderson)]

dewar@merv.cs.nyu.edu (Robert Dewar) writes:

>Fergus 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!

OK, so I guess you have to use some sort of handles instead of pointers.
Hmmm, it's not sounding quite so transparent anymore...
But my question still stands: what happens if the last reference
(handle, pointer, whatever) to a dynamically allocated SNOBOL4 data
structure is stored in a C global variable?

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