Re: [Plplot-devel] plinit, plend, plinit sequence now works, but I am having second thoughts

[Alan W. I. <ir...@be...>]

On Tue, 10 Dec 2002, Joao Cardoso wrote:

> > Actually, with sunos, memory had to be specifically released by the
> > programme.
>
> Hard to believe! sunos is unix. Unless you are talking of shared memory, as in
> that case the shared memory will stay (usable by other processes) in the
> system, even when the program who allocate it exits. It must be explicitly
> released.

I was probably talking about shared memory.....(with my further questions
about this carried on privately).

> > My own feeling is not too many of our users currently use the
> > plinit/plend/plinit sequence so it wouldn't be too much of a burden to ask
> > them to shift to plinit/plend1/plinit. But if this really is too much of a
> > burden, we also have the option of adding another function (pllibfree?)
>
> remember to not polute the API. We should be carefull with this issue. I think
> that plinit/plend1 will be fine.

Good.

> Also, our library does not has a specific entry point to initialize it, and
> thus it doesn't make much sense to have one to finish using it.

Maurice set this up some time ago.  It has not been well advertised so I
will mention the details again.  plinit (which every initialization of
plplot must go through) calls pllib_init.  The first call to pllib_init
initializes the library including memory for the dynamic driver
infrastructure as well as the memory for libltdl.  Thus, it makes sense to
have a function (the very last call to libplplot) which releases the memory
that was allocated as part of the library initialization

> This is a difficult problem to solve, releasing all allocated memory. For
> example, when one use strdup(), or our plstrdup() version, we might lost the
> track of the allocated memory -- that's why valgrind reports "definitively
> lost fragments"

Yes, you would have to be careful.  But a start is to at least release
the libltdl memory which is easy to do.

So has a consensus been reached here to use plend for this library memory
release task with appropriate plend =>plend1 adjustments to the x octave
scripts?

Alan