Actually, perhaps a slightly better question would be: how is Julia's gc implemented? When the gc is called (which I understand could happen at any time), does it search the stack for valid references to objects?
If so, then I think I can answer my own question. The LLVM optimiser could in theory reuse the space in which a pointer lives, for something else, so long as it can prove the value is not used again. That's something outside of Julia's control, and so there's no guarantee the object associated with a variable will live to the end of scope. Bill. On Thursday, 1 October 2015 12:23:43 UTC+2, Bill Hart wrote: > > Is there any relationship between Julia's lexical scoping and garbage > collection? > > What I mean is: if I have a function inside which is a variable which is > not used from some point onwards in the function, does the object live on > until the end of scope or is it possible that it may be gc'd before the end > of the scope of that variable? > > Obviously I'm asking because we want to keep an unsafe pointer to the > internals of some C object which is only used inside that function, but > possibly after the last use of the Julia managed object. > > Shorter version of question: how does Julia decide when it is safe to > clean up a an object bound to a variable that is still in lexical scope? > > (I realise of course that if the variable in question is assigned some > other value there is no longer a valid reference to the object and all bets > are off.) > > Bill. >
