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How much of a win depends on your memory situation, but if you are firing
off perl with any regularity (like more than once every 20 seconds or so)
it is probably beneficial to INSTALL at least portions of perl.

While there is code in perl to remove privileges as it runs you are advised
to NOT INSTALL F<PERL.EXE> with PRIVs!

=head2 Running h2ph to create perl header files (optional) on VMS

If using HP C, ensure that you have extracted loose versions of your 
compiler's header or *.H files.  Be sure to check the contents of:

    SYS$LIBRARY:DECC$RTLDEF.TLB
    SYS$LIBRARY:SYS$LIB_C.TLB
    SYS$LIBRARY:SYS$STARLET_C.TLB

etcetera.

If using GNU cc then also check your GNU_CC:[000000...] tree for the locations
of the GNU cc headers.

=head1 Reporting Bugs

If you come across what you think might be a bug in Perl, please report
it. The issue tracker at L<https://github.com/Perl/perl5/issues> walks you
through the process of creating a bug report and including details of your
installation.

=head1 CAVEATS

Probably the single biggest gotcha in compiling Perl is giving the wrong
switches to MMS/MMK when you build. Use I<exactly> what the configure.com 
script prints!

Be sure that the process that you use to build Perl has a PGFLQUO of at
least 400000.  Be sure to have a correct local time zone to UTC offset
defined (in seconds) in the logical name SYS$TIMEZONE_DIFFERENTIAL before
running the regression test suite.  The SYS$MANAGER:UTC$CONFIGURE_TDF.COM 
procedure will help you set that logical for your system but may require 
system privileges.  For example, a location 5 hours west of UTC (such as 
the US East coast while not on daylight savings time) would have:

    DEFINE SYS$TIMEZONE_DIFFERENTIAL "-18000"

A final thing that causes trouble is leftover pieces from a failed
build.  If things go wrong make sure you do a "(MMK|MMS|make) realclean"
before you rebuild.

=head2 Floating Point Considerations

Prior to 5.8.0, Perl simply accepted the default floating point options of the
C compiler, namely representing doubles with G_FLOAT on Alpha.  Single
precision floating point values are represented in F_FLOAT format when either
D_FLOAT or G_FLOAT is in use for doubles.  Beginning with 5.8.0, Alpha builds
now use IEEE floating point formats by default, which in VMS parlance are S_FLOAT
for singles and T_FLOAT for doubles.  Itanium builds have always used IEEE by
default. The  available non-default options are D_FLOAT or G_FLOAT on Alpha
or Itanium.

The use of IEEE introduces NaN, infinity, and denormalization capabilities not
available with D_FLOAT and G_FLOAT.  When using one of those non-IEEE formats,
silent underflow and overflow are emulated in the conversion of strings to
numbers, but it is preferable to get the real thing by using IEEE where possible.
You are likely to see quite a few test failures when not using IEEE floating point.

Regardless of what floating point format you consider preferable, be aware
that the choice may have an impact on compatibility with external libraries,
such as database interfaces, and with existing data, such as data created with
the C<pack> function and written to disk, or data stored via the Storable
extension.  For example, a C<pack("d", $foo)")> will create a D_FLOAT,
G_FLOAT, or T_FLOAT depending on what your Perl was configured with.  When
written to disk, the value can only be retrieved later by a Perl configured
with the same floating point option that was in effect when it was created.

To obtain a non-IEEE build, simply answer no to the "Use IEEE math?" question
during the configuration or specify -"Uuseieee" as a parameter to configure.com
on the command line.

=head1 Mailing Lists

There are several mailing lists available to the Perl porter.  For VMS
specific issues (including both Perl questions and installation problems)
there is the VMSPERL mailing list.  It is usually a low-volume (10-12
messages a week) mailing list.

To subscribe, send a mail message to VMSPERL-SUBSCRIBE@PERL.ORG. The VMSPERL
mailing list address is VMSPERL@PERL.ORG.  Any mail sent there gets echoed
to all subscribers of the list.  There is an archive of the list
on the web at:

    L<https://www.nntp.perl.org/group/perl.vmsperl/>

To unsubscribe from VMSPERL send a message to VMSPERL-UNSUBSCRIBE@PERL.ORG.
Be sure to do so from the subscribed account that you are canceling.

=head2 Web sites for Perl on VMS

Vmsperl pages on the web include:

    L<http://www.sidhe.org/vmsperl/index.html>
    L<https://www.cpan.org/modules/by-module/VMS/>
    L<https://www.nntp.perl.org/group/perl.vmsperl/>
    L<https://sourceforge.net/projects/vmsperlkit/>

=head1 SEE ALSO

Perl information for users and programmers about the port of perl to VMS is
available from the [.pod]perlvms.pod file that gets installed as L<perlvms>.
For administrators the perlvms document also includes a detailed discussion 
of extending vmsperl with CPAN modules after Perl has been installed.

=head1 AUTHORS

Originally by Charles Bailey bailey@newman.upenn.edu.  See the git repository
for history.

=head1 ACKNOWLEDGEMENTS

A real big thanks needs to go to Charles Bailey
bailey@newman.upenn.edu, who is ultimately responsible for Perl 5.004