Queue cleanup

[Paul Rubin]

Steven D'Aprano <steve-REMOVE-THIS at cybersource.com.au> writes:
> I'm not saying that ref counting systems can avoid incrementing and 
> decrementing the ref counts. That would be silly. But I'm saying that it 
> is an accident of implementation that writing C extensions requires you 
> to manually manage the counts yourself. That's a side-effect of 
> permitting coders to write C extensions in pure C, rather than in some 
> intermediate language which handles the ref counts for you but otherwise 
> compiles like C. If people cared enough, they could (probably) make the C 
> compiler handle it for them, just as it currently handles incrementing 
> and decrementing the return stack. 

I guess that is how the so-called smart pointers in the Boost C++
template library work.  I haven't used them so I don't have personal
experience with how convenient or reliable they are, or what kinds of
constraints they imposed on programming style.  I've always felt a bit
suspicious of them though, and I seem to remember Alex Martelli (I hope
he shows up here again someday) advising against using them.

I don't think a C compiler could really manage automatic decrementing
while still being C.  Think especially of the common style of exception
handling in C using longjmp.