NetNews Usenet Archive 1993 #1/NN_1993_1.iso/spool/comp/sys/hp48/6949

Internet Message Format | 1993-01-12 | 1.6 KB

From: [e-mail] (william j. levenson)
Date: Tue, 12 Jan 1993 22:40:02 GMT
Subject: Re: Moving directories (was: Re: some general questions for HP48)
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Jurgen N.E. Bos writes that recalling the contents of a directory to the
stack, purging the original directory, and then storing it in a new place
can loose your directory.  Well, I just tried it and it worked fine.  I
initially thought that it might cause a problem also.  But, I think what
must happen is that when PGDIR goes through and purges each variable in
the directory, it sees that the variable is referenced on the stack,
copies that object to TEMPOB area and updates the reference.

That's the only thing I can think of because if I recall a directory's
contents to the stack and then PURGE a variable in the directory, sure
enough, the copy on the stack is changed as well (because the object on
the stack is just a pointer to memory, of course).  It seems that PURGE
does not check for references inside directory objects on the stack.  But
it DOES  seem that PGDIR does this for you.

I seem to recall Joe Horn and Bill Wickes discussing this type of stuff
 and the FPGIDR (I'm not sure if that name is right) program.  I'm not
sure if they touched on this topic, but it's on one of the goodies discs,
if you're interested.

Let me know if I'm off base here.

Bill Levenson