| Newsgroups |
perl.cvs.perlfaq |
| Message-ID |
<[email protected]> |
cvsuser 02/05/06 06:11:13
Modified: . perlfaq3.pod
Log:
How can I free an array or hash so my program shrinks?
* removed comments on particular operating systems since they
were a bit dated
* added comment about Perl's own malloc versus the OS supplied one
Revision Changes Path
1.22 +9 -12 perlfaq/perlfaq3.pod
Index: perlfaq3.pod
===================================================================
RCS file: /cvs/public/perlfaq/perlfaq3.pod,v
retrieving revision 1.21
retrieving revision 1.22
diff -u -w -r1.21 -r1.22
--- perlfaq3.pod 28 Apr 2002 15:51:10 -0000 1.21
+++ perlfaq3.pod 6 May 2002 13:11:13 -0000 1.22
@@ -1,6 +1,6 @@
=head1 NAME
-perlfaq3 - Programming Tools ($Revision: 1.21 $, $Date: 2002/04/28 15:51:10 $)
+perlfaq3 - Programming Tools ($Revision: 1.22 $, $Date: 2002/05/06 13:11:13 $)
=head1 DESCRIPTION
@@ -617,17 +617,14 @@
=head2 How can I free an array or hash so my program shrinks?
-You can't. On most operating systems, memory allocated to a program
-can never be returned to the system. That's why long-running programs
-sometimes re-exec themselves. Some operating systems (notably,
-FreeBSD and Linux) allegedly reclaim large chunks of memory that is no
-longer used, but it doesn't appear to happen with Perl (yet). The Mac
-appears to be the only platform that will reliably (albeit, slowly)
-return memory to the OS.
-
-We've had reports that on Linux (Redhat 5.1) on Intel, C<undef
-$scalar> will return memory to the system, while on Solaris 2.6 it
-won't. In general, try it yourself and see.
+You usually can't. On most operating systems, memory
+allocated to a program can never be returned to the system.
+That's why long-running programs sometimes re-exec
+themselves. Some operating systems (notably, systems that
+use mmap(2) for allocating large chunks of memory) can
+reclaim memory that is no longer used, but on such systems,
+perl must be configured and compiled to use the OS's malloc,
+not perl's.
However, judicious use of my() on your variables will help make sure
that they go out of scope so that Perl can free up that space for