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  #   ˆl–ßi~” ”ÂXÔåÆEpN©‹Fÿ¿„"`ÂÁ ?÷     =head1 NAME

Config - access Perl configuration information

=head1 SYNOPSIS

    use Config;
    if ($Config{usethreads}) {
	print "has thread support\n"
    } 

    use Config qw(myconfig config_sh config_vars config_re);

    print myconfig();

    print config_sh();

    print config_re();

    config_vars(qw(osname archname));


=head1 DESCRIPTION

The Config module contains all the information that was available to
the C<Configure> program at Perl build time (over 900 values).

Shell variables from the F<config.sh> file (written by Configure) are
stored in the readonly-variable C<%Config>, indexed by their names.

Values stored in config.sh as 'undef' are returned as undefined
values.  The perl C<exists> function can be used to check if a
named variable exists.

For a description of the variables, please have a look at the
Glossary file, as written in the Porting folder, or use the url:
http://perl5.git.perl.org/perl.git/blob/HEAD:/Porting/Glossary

=over 4

=item myconfig()

Returns a textual summary of the major perl configuration values.
See also C<-V> in L<perlrun/Command Switches>.

=item config_sh()

Returns the entire perl configuration information in the form of the
original config.sh shell variable assignment script.

=item config_re($regex)

Like config_sh() but returns, as a list, only the config entries who's
names match the $regex.

=item config_vars(@names)

Prints to STDOUT the values of the named configuration variable. Each is
printed on a separate line in the form:

  name='value';

Names which are unknown are output as C<name='UNKNOWN';>.
See also C<-V:name> in L<perlrun/Command Switches>.

=item bincompat_options()

Returns a list of C pre-processor options used when compiling this F<perl>
binary, which affect its binary compatibility with extensions.
C<bincompat_options()> and C<non_bincompat_options()> are shown together in
the output of C<perl -V> as I<Compile-time options>.

=item non_bincompat_options()

Returns a list of C pre-processor options used when compiling this F<perl>
binary, which do not affect binary compatibility with extensions.

=item compile_date()

Returns the compile date (as a string), equivalent to what is shown by
C<perl -V>

=item local_patches()

Returns a list of the names of locally applied patches, equivalent to what
is shown by C<perl -V>.

=item header_files()

Returns a list of the header files that should be used as dependencies for
XS code, for this version of Perl on this platform.

=back

=head1 EXAMPLE

Here's a more sophisticated example of using %Config:

    use Config;
    use strict;

    my %sig_num;
    my @sig_name;
    unless($Config{sig_name} && $Config{sig_num}) {
	die "No sigs?";
    } else {
	my @names = split ' ', $Config{sig_name};
	@sig_num{@names} = split ' ', $Config{sig_num};
	foreach (@names) {
	    $sig_name[$sig_num{$_}] ||= $_;
	}   
    }

    print "signal #17 = $sig_name[17]\n";
    if ($sig_num{ALRM}) { 
	print "SIGALRM is $sig_num{ALRM}\n";
    }   

=head1 WARNING

Because this information is not stored within the perl executable
itself it is possible (but unlikely) that the information does not
relate to the actual perl binary which is being used to access it.

The Config module is installed into the architecture and version
specific library directory ($Config{installarchlib}) and it checks the
perl version number when loaded.

The values stored in config.sh may be either single-quoted or
double-quoted. Double-quoted strings are handy for those cases where you
need to include escape sequences in the strings. To avoid runtime variable
interpolation, any C<$> and C<@> characters are replaced by C<\$> and
C<\@>, respectively. This isn't foolproof, of course, so don't embed C<\$>
or C<\@> in double-quoted strings unless you're willing to deal with the
consequences. (The slashes will end up escaped and the C<$> or C<@> will
trigger variable interpolation)

=head1 GLOSSARY

Most C<Config> variables are determined by the C<Configure> script
on platforms supported by it (which i