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   1  package vmsish;
   2  
   3  our $VERSION = '1.02';
   4  
   5  =head1 NAME
   6  
   7  vmsish - Perl pragma to control VMS-specific language features
   8  
   9  =head1 SYNOPSIS
  10  
  11      use vmsish;
  12  
  13      use vmsish 'status';    # or '$?'
  14      use vmsish 'exit';
  15      use vmsish 'time';
  16  
  17      use vmsish 'hushed';
  18      no vmsish 'hushed';
  19      vmsish::hushed($hush);
  20  
  21      use vmsish;
  22      no vmsish 'time';
  23  
  24  =head1 DESCRIPTION
  25  
  26  If no import list is supplied, all possible VMS-specific features are
  27  assumed.  Currently, there are four VMS-specific features available:
  28  'status' (a.k.a '$?'), 'exit', 'time' and 'hushed'.
  29  
  30  If you're not running VMS, this module does nothing.
  31  
  32  =over 6
  33  
  34  =item C<vmsish status>
  35  
  36  This makes C<$?> and C<system> return the native VMS exit status
  37  instead of emulating the POSIX exit status.
  38  
  39  =item C<vmsish exit>
  40  
  41  This makes C<exit 1> produce a successful exit (with status SS$_NORMAL),
  42  instead of emulating UNIX exit(), which considers C<exit 1> to indicate
  43  an error.  As with the CRTL's exit() function, C<exit 0> is also mapped
  44  to an exit status of SS$_NORMAL, and any other argument to exit() is
  45  used directly as Perl's exit status.
  46  
  47  =item C<vmsish time>
  48  
  49  This makes all times relative to the local time zone, instead of the
  50  default of Universal Time (a.k.a Greenwich Mean Time, or GMT).
  51  
  52  =item C<vmsish hushed>
  53  
  54  This suppresses printing of VMS status messages to SYS$OUTPUT and
  55  SYS$ERROR if Perl terminates with an error status.  and allows
  56  programs that are expecting "unix-style" Perl to avoid having to parse
  57  VMS error messages.  It does not suppress any messages from Perl
  58  itself, just the messages generated by DCL after Perl exits.  The DCL
  59  symbol $STATUS will still have the termination status, but with a
  60  high-order bit set:
  61  
  62  EXAMPLE:
  63      $ perl -e"exit 44;"                             Non-hushed error exit
  64      %SYSTEM-F-ABORT, abort                          DCL message
  65      $ show sym $STATUS
  66        $STATUS == "%X0000002C"
  67  
  68      $ perl -e"use vmsish qw(hushed); exit 44;"      Hushed error exit
  69      $ show sym $STATUS
  70        $STATUS == "%X1000002C"
  71  
  72  The 'hushed' flag has a global scope during compilation: the exit() or
  73  die() commands that are compiled after 'vmsish hushed' will be hushed
  74  when they are executed.  Doing a "no vmsish 'hushed'" turns off the
  75  hushed flag.
  76  
  77  The status of the hushed flag also affects output of VMS error
  78  messages from compilation errors.   Again, you still get the Perl
  79  error message (and the code in $STATUS)
  80  
  81  EXAMPLE:
  82      use vmsish 'hushed';    # turn on hushed flag
  83      use Carp;          # Carp compiled hushed
  84      exit 44;           # will be hushed
  85      croak('I die');    # will be hushed
  86      no vmsish 'hushed';     # turn off hushed flag
  87      exit 44;           # will not be hushed
  88      croak('I die2'):   # WILL be hushed, croak was compiled hushed
  89  
  90  You can also control the 'hushed' flag at run-time, using the built-in
  91  routine vmsish::hushed().  Without argument, it returns the hushed status.
  92  Since vmsish::hushed is built-in, you do not need to "use vmsish" to call
  93  it.
  94  
  95  EXAMPLE:
  96      if ($quiet_exit) {
  97          vmsish::hushed(1);
  98      } 
  99      print "Sssshhhh...I'm hushed...\n" if vmsish::hushed();
 100      exit 44;
 101  
 102  Note that an exit() or die() that is compiled 'hushed' because of "use
 103  vmsish" is not un-hushed by calling vmsish::hushed(0) at runtime.
 104  
 105  The messages from error exits from inside the Perl core are generally
 106  more serious, and are not suppressed.
 107  
 108  =back
 109  
 110  See L<perlmod/Pragmatic Modules>.
 111  
 112  =cut
 113  
 114  my $IsVMS = $^O eq 'VMS';
 115  
 116  sub bits {
 117      my $bits = 0;
 118      my $sememe;
 119      foreach $sememe (@_) {
 120      # Those hints are defined in vms/vmsish.h :
 121      # HINT_M_VMSISH_STATUS and HINT_M_VMSISH_TIME
 122          $bits |= 0x40000000, next if $sememe eq 'status' || $sememe eq '$?';
 123      $bits |= 0x80000000, next if $sememe eq 'time';
 124      }
 125      $bits;
 126  }
 127  
 128  sub import {
 129      return unless $IsVMS;
 130  
 131      shift;
 132      $^H |= bits(@_ ? @_ : qw(status time));
 133      my $sememe;
 134  
 135      foreach $sememe (@_ ? @_ : qw(exit hushed)) {
 136          $^H{'vmsish_exit'}   = 1 if $sememe eq 'exit';
 137          vmsish::hushed(1) if $sememe eq 'hushed';
 138      }
 139  }
 140  
 141  sub unimport {
 142      return unless $IsVMS;
 143  
 144      shift;
 145      $^H &= ~ bits(@_ ? @_ : qw(status time));
 146      my $sememe;
 147  
 148      foreach $sememe (@_ ? @_ : qw(exit hushed)) {
 149          $^H{'vmsish_exit'}   = 0 if $sememe eq 'exit';
 150          vmsish::hushed(0) if $sememe eq 'hushed';
 151      }
 152  }
 153  
 154  1;