[lazarus] Clean build from nothing

cryst cryst at golden.net
Wed Jun 25 10:32:16 EDT 2003


I think the point was that the libs are so. (shared object). Whereas fpc is
static. (please correct me if I'm wrong!) If you have many fpc programs each
will have it's own copy of the library in memory. This probably hasn't
become an issue since most often you only use one or two fpc programs at a
time, but what happens when you have a large app that uses litereally
thousands of instances of a fpc program. Does that mean that there is
thousands of instances of the same code in memory?  The kernel will be so
busy swaping out processes that nothing would get done.

Chris

----- Original Message -----
From: "Marco van de Voort" <marcov at stack.nl>
To: <lazarus at miraclec.com>
Sent: Wednesday, June 25, 2003 6:25 AM
Subject: Re: [lazarus] Clean build from nothing


> > > If you can't think of a use for the C library, then why do you ask us
to
> > > use it ? ;-)
> >
> > Well, I can :)
> >
> > Libraries are loaded into the memory only once, no matter how many
processes
> > use them. Thus the memory used for the library is shared. This heavily
> > reduces memory needs for a system.
>
> This has nothing to do with that. FPC only use about 50 primitives from
> the kernel, that would be otherwise used from libc.
>
> It doesn't matter for memory usage where I get them. The kernel is also
> resident it seems.
>
> So in theory the kernel interface could be beneficial even. Unused parts
of
> the libc can be swapped out when a heavy FPC program is running.
>
> > I think, the current free pascal concept (avoiding C libraries, mainly
> > libc) is usable only because on a tipical system only a few pascal
> > processes run at once; the rest of the system is written in C, so enough
> > memory remains to run the pascal programs :)
>
> The main reason why this is important is for OS tools, like the shell and
> make. They are often called recursively. But if one of them were FPC
based,
> you'd have a 100kb redundancy with a FPC rtl shared lib, and the C ones.
> Big deal :-)
>
> Don't forget we only need a very small subset of libc, (say 10-40 kb of
it's
> 800). The rest is not OS library, but C language runtime, which we can't
> use anyway.
>
>
> Again, theory and practice in Unix advocacy are WIDE apart ;-)
>
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