Michael G Schwern wrote:
>
> On Wed, Oct 02, 2002 at 01:50:56PM +0200, H.Merijn Brand wrote:
> > SYNOPSIS
> > use Devel::Internals;
>
> A little broad. Perhaps Devel::Memory?
>
> > my $end = sbrk ();
> >
> > my @array = (1..10000);
> > print "The creation of this array used ",
> > sbrk () - $end, "bytes\n";
> >
> > # Easier
> > use Devel::Internals;
> >
> > my @array = (1..10000);
> > MemUsed "creation of array";
> >
> > my @dup = @array;
> > MemUsed "duplication of array";
> >
> > DESCRIPTION
> > sbrk
> > returns the current memory top. See sbrk(2) manual page
>
> I realize that sbrk() is a familiar concept to deep C programmers on
> BSD-style systems, but in order for this to be useful to Perl
> programmers, or even users not familiar with BSD, you're going to have
> to name it something more descriptive than sbrk() and explain better
> what it does.
If "what it does" is merely return the value of the C sbrk() function,
then IMHO, sbrk() is a perfectly good name.
However, as to other possible names -- how about ProcessSize() ? I'm
not sure if this is really a valid description of what sbrk() returns,
though.
> It can still do the same thing as sbrk(), and you might even want to
> leave in an alias to sbrk() so BSD core hackers can feel all warm and
> fuzzy.
>
> > MemUsed ($msg)
> > Used in void context reports the number of bytes used
> > since the previous call to MemUsed with the message passed
>
> Global state is a Bad Thing. Consider when you have two different,
> unrelated subroutines both calling MemUsed() in the same program.
> foo() calls MemUsed() then bar() then foo() calls MemUsed() again
> expecting to get the memory used since it's last call but it's
> actually getting the memory used since bar() last called it.
Perhaps MemUsed should keep track of where it was called from?
Eg:
sub MemUsed {
my $sbrk = sbrk();
my $prior = \ $sbrks{join "::", (caller(1))[3, 0] };
if( defined $$prior ) {
my $diff = $sbrk - $$prior;
print ....;
}
$$prior = $sbrk;
}
This works fine as long as there is no recursion.
If there *is* recursion, then the user need to stuff the return value of
sbrk() in a variable, or somesuch.
--
How many Monks would a Chipmonk chip,
if a Chipmonk could chip Monks?
