<p>What free and commercial garbage collection libraries are available for C++, and what are the pros and cons of each?</p>

<p>I am interested in hard-won lessons from actual use in the field, not marketing or promotional blurb.</p>

<p>There is no need to elaborate on the usual trade offs associated with automatic garbage collection, but please do mention the algorithms used (reference counting, mark and sweep, incremental, etc.) and briefly summarise the consequences.</p>

The Boehm garbage collector
is freely available, and supposedly rather good (no first hand experience myself)
Theoretical paper (in PDF) about
C++0x proposal for the Boehm garbage collector
It was originally said to make C++0x
, but will not make it after all
(due to time constraints I suppose).
Proprosal N2670
(minimal support for garbage collectors) did get approved in june 2008 though, so as compiler implementations pick up on this, and the standard gets finalised, the garbage collection world out there for C++ is sure to change...