lib/perl5/5.8.8/vmsish.pm

   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;