perlvms.pod

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    $ perl -e "print join(' ',@ARGV)" perl.*
    perl.c perl.exe perl.h perl.obj

in the following triple quoted manner:

    $ perl -e "print join(' ',@ARGV)" """perl.*"""
    perl.*

In both the case of unquoted command line arguments or in calls
to C<glob()> VMS wildcard expansion is performed. (csh-style
wildcard expansion is available if you use C<File::Glob::glob>.)
If the wildcard filespec contains a device or directory 
specification, then the resultant filespecs will also contain 
a device and directory; otherwise, device and directory 
information are removed.  VMS-style resultant filespecs will 
contain a full device and directory, while Unix-style 
resultant filespecs will contain only as much of a directory 
path as was present in the input filespec.  For example, if 
your default directory is Perl_Root:[000000], the expansion 
of C<[.t]*.*> will yield filespecs  like 
"perl_root:[t]base.dir", while the expansion of C<t/*/*> will 
yield filespecs like "t/base.dir".  (This is done to match 
the behavior of glob expansion performed by Unix shells.) 

Similarly, the resultant filespec will contain the file version
only if one was present in the input filespec.


=head2 Pipes

Input and output pipes to Perl filehandles are supported; the 
"file name" is passed to lib$spawn() for asynchronous 
execution.  You should be careful to close any pipes you have 
opened in a Perl script, lest you leave any "orphaned" 
subprocesses around when Perl exits. 

You may also use backticks to invoke a DCL subprocess, whose 
output is used as the return value of the expression.  The 
string between the backticks is handled as if it were the
argument to the C<system> operator (see below).  In this case,
Perl will wait for the subprocess to complete before continuing. 

The mailbox (MBX) that perl can create to communicate with a pipe
defaults to a buffer size of 512.  The default buffer size is
adjustable via the logical name PERL_MBX_SIZE provided that the
value falls between 128 and the SYSGEN parameter MAXBUF inclusive.
For example, to double the MBX size from the default within
a Perl program, use C<$ENV{'PERL_MBX_SIZE'} = 1024;> and then
open and use pipe constructs.  An alternative would be to issue
the command:

    $ Define PERL_MBX_SIZE 1024

before running your wide record pipe program.  A larger value may
improve performance at the expense of the BYTLM UAF quota.

=head1 PERL5LIB and PERLLIB

The PERL5LIB and PERLLIB logical names work as documented in L<perl>,
except that the element separator is '|' instead of ':'.  The
directory specifications may use either VMS or Unix syntax.

=head1 The Perl Forked Debugger

The Perl forked debugger places the debugger commands and output in a
separate X-11 terminal window so that commands and output from multiple
processes are not mixed together.

Perl on VMS supports an emulation of the forked debugger when Perl is
run on a VMS system that has X11 support installed.

To use the forked debugger, you need to have the default display set to an
X-11 Server and some environment variables set that Unix expects.

The forked debugger requires the environment variable C<TERM> to be C<xterm>,
and the environment variable C<DISPLAY> to exist.  C<xterm> must be in
lower case.

  $define TERM "xterm"

  $define DISPLAY "hostname:0.0"

Currently the value of C<DISPLAY> is ignored.  It is recommended that it be set
to be the hostname of the display, the server and screen in UNIX notation.  In
the future the value of DISPLAY may be honored by Perl instead of using the
default display.

It may be helpful to always use the forked debugger so that script I/O is
separated from debugger I/O.  You can force the debugger to be forked by
assigning a value to the logical name <PERLDB_PIDS> that is not a process
identification number.

  $define PERLDB_PIDS XXXX


=head1 PERL_VMS_EXCEPTION_DEBUG

The PERL_VMS_EXCEPTION_DEBUG being defined as "ENABLE" will cause the VMS
debugger to be invoked if a fatal exception that is not otherwise
handled is raised.  The purpose of this is to allow debugging of
internal Perl problems that would cause such a condition.

This allows the programmer to look at the execution stack and variables to
find out the cause of the exception.  As the debugger is being invoked as
the Perl interpreter is about to do a fatal exit, continuing the execution
in debug mode is usally not practical.

Starting Perl in the VMS debugger may change the program execution
profile in a way that such problems are not reproduced.

The C<kill> function can be used to test this functionality from within
a program.

In typical VMS style, only the first letter of the value of this logical
name is actually checked in a case insensitive mode, and it is considered
enabled if it is the value "T","1" or "E".

This logical name must be defined before Perl is started.

=head1 Command line

=head2 I/O redirection and backgrounding

Perl for VMS supports redirection of input and output on the 
command line, using a subset of Bourne shell syntax:

=over 4

=item *

C<E<lt>file> reads stdin from C<file>,

=item *

C<E<gt>file> writes stdout to C<file>,

=item *

C<E<gt>E<gt>file> appends stdout to C<file>,

=item *

C<2E<gt>file> writes stderr to C<file>,

=item *

C<2E<gt>E<gt>file> appends stderr to C<file>, and

=item *

C<< 2>&1 >> redirects stderr to stdout.

=back

In addition, output may be piped to a subprocess, using the  
character '|'.  Anything after this character on the command 
line is passed to a subprocess for execution; the subprocess 
takes the output of Perl as its input.

Finally, if the command line ends with '&', the entire 
command is run in the background as an asynchronous 
subprocess.

=head2 Command line switches

The following command line switches behave differently under
VMS than described in L<perlrun>.  Note also that in order
to pass uppercase switches to Perl, you need to enclose
them in double-quotes on the command line, since the CRTL
downcases all unquoted strings.

On newer 64 bit versions of OpenVMS, a process setting now
controls if the quoting is needed to preserve the case of
command line arguments.

=over 4

=item -i

If the C<-i> switch is present but no extension for a backup
copy is given, then inplace editing creates a new version of
a file; the existing copy is not deleted.  (Note that if
an extension is given, an existing file is renamed to the backup
file, as is the case under other operating systems, so it does
not remain as a previous version under the original filename.)

=item -S

If the C<"-S"> or C<-"S"> switch is present I<and> the script
name does not contain a directory, then Perl translates the
logical name DCL$PATH as a searchlist, using each translation
as a directory in which to look for the script.  In addition,
if no file type is specified, Perl looks in each directory
for a file matching the name specified, with a blank type,
a type of F<.pl>, and a type of F<.com>, in that order.

=item -u

The C<-u> switch causes the VMS debugger to be invoked
after the Perl program is compiled, but before it has
run.  It does not create a core dump file.

=back

=head1 Perl functions

As of the time this document was last revised, the following 
Perl functions were implemented in the VMS port of Perl 
(functions marked with * are discussed in more detail below):

    file tests*, abs, alarm, atan, backticks*, binmode*, bless,
    caller, chdir, chmod, chown, chomp, chop, chr,
    close, closedir, cos, crypt*, defined, delete, die, do, dump*, 
    each, endgrent, endpwent, eof, eval, exec*, exists, exit, exp, 
    fileno, flock  getc, getgrent*, getgrgid*, getgrnam, getlogin, getppid,
    getpwent*, getpwnam*, getpwuid*, glob, gmtime*, goto,
    grep, hex, ioctl, import, index, int, join, keys, kill*,
    last, lc, lcfirst, lchown*, length, link*, local, localtime, log, lstat, m//,
    map, mkdir, my, next, no, oct, open, opendir, ord, pack,
    pipe, pop, pos, print, printf, push, q//, qq//, qw//,
    qx//*, quotemeta, rand, read, readdir, readlink*, redo, ref, rename,
    require, reset, return, reverse, rewinddir, rindex,
    rmdir, s///, scalar, seek, seekdir, select(internal),
    select (system call)*, setgrent, setpwent, shift, sin, sleep,
    socketpair, sort, splice, split, sprintf, sqrt, srand, stat,
    study, substr, symlink*, sysread, system*, syswrite, tell,
    telldir, tie, time, times*, tr///, uc, ucfirst, umask,
    undef, unlink*, unpack, untie, unshift, use, utime*,
    values, vec, wait, waitpid*, wantarray, warn, write, y///

The following functions were not implemented in the VMS port, 
and calling them produces a fatal error (usually) or 
undefined behavior (rarely, we hope):

    chroot, dbmclose, dbmopen, fork*, getpgrp, getpriority,  
    msgctl, msgget, msgsend, msgrcv, semctl,
    semget, semop, setpgrp, setpriority, shmctl, shmget,
    shmread, shmwrite, syscall

The following functions are available on Perls compiled with Dec C
5.2 or greater and running VMS 7.0 or greater:

    truncate

The following functions are available on Perls built on VMS 7.2 or
greater:

    fcntl (without locking)

The following functions may or may not be implemented, 
depending on what type of socket support you've built into 
your copy of Perl:

    accept, bind, connect, getpeername,
    gethostbyname, getnetbyname, getprotobyname,
    getservbyname, gethostbyaddr, getnetbyaddr,
    getprotobynumber, getservbyport, gethostent,
    getnetent, getprotoent, getservent, sethostent,
    setnetent, setprotoent, setservent, endhostent,
    endnetent, endprotoent, endservent, getsockname,
    getsockopt, listen, recv, select(system call)*,
    send, setsockopt, shutdown, socket

The following function is available on Perls built on 64 bit OpenVMS v8.2
with hard links enabled on an ODS-5 formatted build disk.  CRTL support
is in principle available as of OpenVMS v7.3-1, and better configuration
support could detect this.

    link

The following functions are available on Perls built on 64 bit OpenVMS
v8.2 and later.  CRTL support is in principle available as of OpenVMS
v7.3-2, and better configuration support could detect this.

   getgrgid, getgrnam, getpwnam, getpwuid,
   setgrent, ttyname

The following functions are available on Perls built on 64 bit OpenVMS v8.2
and later.  

   statvfs, socketpair

=over 4

=item File tests

The tests C<-b>, C<-B>, C<-c>, C<-C>, C<-d>, C<-e>, C<-f>,
C<-o>, C<-M>, C<-s>, C<-S>, C<-t>, C<-T>, and C<-z> work as
advertised.  The return values for C<-r>, C<-w>, and C<-x>
tell you whether you can actually access the file; this may
not reflect the UIC-based file protections.  Since real and
effective UIC don't differ under VMS, C<-O>, C<-R>, C<-W>,
and C<-X> are equivalent to C<-o>, C<-r>, C<-w>, and C<-x>.
Similarly, several other tests, including C<-A>, C<-g>, C<-k>,
C<-l>, C<-p>, and C<-u>, aren't particularly meaningful under
VMS, and the values returned by these tests reflect whatever
your CRTL C<stat()> routine does to the equivalent bits in the
st_mode field.  Finally, C<-d> returns true if passed a device
specification without an explicit directory (e.g. C<DUA1:>), as
well as if passed a directory.

There are DECC feature logical names AND ODS-5 volume attributes that
also control what values are returned for the date fields.

Note: Some sites have reported problems when using the file-access