Re: [9fans] pascal, TeX

["Douglas A. Gwyn" <DAGwyn@null.net>]

D De Villiers wrote:
> According to my knowledge - Java was the first language that implemented
> garbage collection...Neather C/C++ or Pascal (Delphi etc) have garbage
> collection and memory must be manually located/delocated etc.

Actually, garbage collection was implemented in some very
old languages such as LISP.

C++ does have what amounts to garbage collection plus other
programmer-controllable actions in its object destructors,
which are automatically invoked when objects go out of scope.

C has had garbage collectors implemented for it; for example,
somebody (I think it was Rob) made heavy use of gcalloc() in
the Blit family, both in the terminal's operating system and
in application programs.

The basic problem with garbage collection in C is nt in doing
it, but in doing it efficiently.  The main reason it is hard
is that C has excellent support for pointer arithmetic, so a
program can manufacture valid pointers in ways that are hard
to track, and a garbage collector can't (with a reasonable
amount of work) be sure when there is no pointer remaining
that could be used to access an object.  Nevertheless, there
have been some clever "good enough" garbage collectors
designed for use with C.  It's not obvious that they are
needed, since C has a long heritage of the programmer making
explicit calls to free() to deallocate dynamic objects.