da Silva, Joe wrote:
> > From: Clarence Verge [SMTP:[EMAIL PROTECTED]]
> > When the application launches the child by EXEC, DOS gives the child ALL
> > the file properties that the parent had as long as the parent didn't
> > specifically say NO to some things/files. In addition, of course,
> > the child can get all the properties that the parent had "inherited"
> > from DOS, again, as long as the parent doesn't say "NO".
> > The INT21fun3D (Open file handle) actually has an "inherit" bit, which
> > when set to 1 makes that file private to the parent.
> >
> [da Silva, Joe]
>
> Yes, that's what I understood, in general terms, from
> what you were saying, and from those references you
> quoted. But what does that mean specifically, for the
> child process? In other words, how does this "fit in"
> with a standard application, which simply says to DOS,
> "I want to open file 'ABC.XYZ', in Write mode", when
> said application is exec'ed by another? Or does the child
> application do something different, instead, to access
> a file that the parent has already "opened for it"? As I
> said, my perspective is HLL, so for me an application
> simply tries to open a file in whichever mode it needs,
> and then DOS either obliges or else tells the application
> to "take a hike" ...
Exactly.
I was going to expand on the above, but didn't want to ramble any further.
The "child" is not special. It is any self-consistent piece of code that
is capable of being launched at the DOS prompt. It needs to know nothing
of it's predecessors (unless you want it to), and it can assume it was
launched by DOS. To be perfectly clear, it can be any program on your HD.
A .bat is a special case, and not included here. (different can of worms)
Likewise, the "parent" can be any program that can run. It can be DOS, or
any application, (child of DOS) or even an application launched by another
application (child of child, grandchild of DOS), until you run out of
resources. There is no difference between parent and child except "pecking"
order.
It looks like there are some interesting "tricky bits" that I would like
to explore here myself, but alas, I lack the time right now. <g>
- Clarence Verge
--
- Help stamp out FATWARE. As a start visit: http://home.arachne.cz/
--
