t/re/pat_advanced.t: Add some comments

[perl5.git] / README.freebsd

If you read this file _as_is_, just ignore the funny characters you
see.  It is written in the POD format (see pod/perlpod.pod) which is
specifically designed to be readable as is.

=head1 NAME

perlfreebsd - Perl version 5 on FreeBSD systems

=head1 DESCRIPTION

This document describes various features of FreeBSD that will affect how Perl
version 5 (hereafter just Perl) is compiled and/or runs.

=head2 FreeBSD core dumps from readdir_r with ithreads

When perl is configured to use ithreads, it will use re-entrant library calls
in preference to non-re-entrant versions.  There is a bug in FreeBSD's
C<readdir_r> function in versions 4.5 and earlier that can cause a SEGV when
reading large directories. A patch for FreeBSD libc is available
(see L<http://www.freebsd.org/cgi/query-pr.cgi?pr=misc/30631> )
which has been integrated into FreeBSD 4.6.

=head2 C<$^X> doesn't always contain a full path in FreeBSD

perl sets C<$^X> where possible to a full path by asking the operating
system. On FreeBSD the full path of the perl interpreter is found by using
C<sysctl> with C<KERN_PROC_PATHNAME> if that is supported, else by reading
the symlink F</proc/curproc/file>. FreeBSD 7 and earlier has a bug where
either approach sometimes returns an incorrect value
(see L<http://www.freebsd.org/cgi/query-pr.cgi?pr=35703> ).
In these cases perl will fall back to the old behaviour of using C's
C<argv[0]> value for C<$^X>.

=head1 AUTHOR

Nicholas Clark <nick@ccl4.org>, collating wisdom supplied by Slaven Rezic
and Tim Bunce.

Please report any errors, updates, or suggestions to L<mailto:perlbug@perl.org>.