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r1 - 26 May 2008 - TWikiGuest

NAME

vmsish - Perl pragma to control VMS-specific language features

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SYNOPSIS 

    use vmsish;
    use vmsish 'status';        # or '$?'
    use vmsish 'exit';
    use vmsish 'time';
    use vmsish 'hushed';
    no vmsish 'hushed';
    vmsish::hushed($hush);
    use vmsish;
    no vmsish 'time';

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DESCRIPTION

If no import list is supplied, all possible VMS-specific features are assumed. Currently, there are four VMS-specific features available: 'status' (a.k.a '$?'), 'exit', 'time' and 'hushed'. If you're not running VMS, this module does nothing.

vmsish status
This makes $? and system return the native VMS exit status
instead of emulating the POSIX exit status.

vmsish exit
This makes exit 1 produce a successful exit (with status SS$_NORMAL),
instead of emulating UNIX exit(), which considers exit 1 to indicate
an error. As with the CRTL's exit() function, exit 0 is also mapped
to an exit status of SS$_NORMAL, and any other argument to exit() is
used directly as Perl's exit status.

vmsish time
This makes all times relative to the local time zone, instead of the
default of Universal Time (a.k.a Greenwich Mean Time, or GMT).

vmsish hushed
This suppresses printing of VMS status messages to SYS$OUTPUT and
SYS$ERROR if Perl terminates with an error status. and allows
programs that are expecting ``unix-style'' Perl to avoid having to parse
VMS error messages. It does not suppress any messages from Perl
itself, just the messages generated by DCL after Perl exits. The DCL
symbol $STATUS will still have the termination status, but with a
high-order bit set:
EXAMPLE: 
    $ perl -e"exit 44;"                             Non-hushed error exit
    %SYSTEM-F-ABORT, abort                          DCL message
    $ show sym $STATUS
      $STATUS == "%X0000002C"
    $ perl -e"use vmsish qw(hushed); exit 44;"      Hushed error exit
    $ show sym $STATUS
      $STATUS == "%X1000002C"
The 'hushed' flag has a global scope during compilation: the exit() or
die() commands that are compiled after 'vmsish hushed' will be hushed
when they are executed. Doing a ``no vmsish 'hushed''' turns off the
hushed flag.
The status of the hushed flag also affects output of VMS error
messages from compilation errors. Again, you still get the Perl
error message (and the code in $STATUS)
EXAMPLE: 
    use vmsish 'hushed';    # turn on hushed flag
    use Carp;          # Carp compiled hushed
    exit 44;           # will be hushed
    croak('I die');    # will be hushed
    no vmsish 'hushed';     # turn off hushed flag
    exit 44;           # will not be hushed
    croak('I die2'):   # WILL be hushed, croak was compiled hushed
You can also control the 'hushed' flag at run-time, using the built-in
routine vmsish::hushed(). Without argument, it returns the hushed status.
Since vmsish::hushed is built-in, you do not need to ``use vmsish'' to call
it.
EXAMPLE: 
    if ($quiet_exit) {
        vmsish::hushed(1);
    }
    print "Sssshhhh...I'm hushed...\n" if vmsish::hushed();
    exit 44;
Note that an exit() or die() that is compiled 'hushed' because of ``use
vmsish`` is not un-hushed by calling vmsish::hushed(0) at runtime.
The messages from error exits from inside the Perl core are generally
more serious, and are not suppressed.
See Pragmatic Modules in the perlmod manpage.

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