summaryrefslogtreecommitdiff
path: root/gnu/usr.bin/perl/warnings.pl
blob: c02e04c13eaf6353228a974f4c758ac2da3918f8 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
#!/usr/bin/perl
# 
# Regenerate (overwriting only if changed):
#
#    lib/warnings.pm
#    warnings.h
#
# from information hardcoded into this script (the $tree hash), plus the
# template for warnings.pm in the DATA section.
#
# With an argument of 'tree', just dump the contents of $tree and exits.
# Also accepts the standard regen_lib -q and -v args.
#
# This script is normally invoked from regen.pl.

$VERSION = '1.02_02';

BEGIN {
    require 'regen_lib.pl';
    push @INC, './lib';
}
use strict ;

sub DEFAULT_ON  () { 1 }
sub DEFAULT_OFF () { 2 }

my $tree = {

'all' => [ 5.008, {
	'io'		=> [ 5.008, { 	
				'pipe' 		=> [ 5.008, DEFAULT_OFF],
       				'unopened'	=> [ 5.008, DEFAULT_OFF],
       				'closed'	=> [ 5.008, DEFAULT_OFF],
       				'newline'	=> [ 5.008, DEFAULT_OFF],
       				'exec'		=> [ 5.008, DEFAULT_OFF],
       				'layer'		=> [ 5.008, DEFAULT_OFF],
			   }],
     	'syntax'	=> [ 5.008, { 	
				'ambiguous'	=> [ 5.008, DEFAULT_OFF],
			     	'semicolon'	=> [ 5.008, DEFAULT_OFF],
			     	'precedence'	=> [ 5.008, DEFAULT_OFF],
			     	'bareword'	=> [ 5.008, DEFAULT_OFF],
			     	'reserved'	=> [ 5.008, DEFAULT_OFF],
				'digit'		=> [ 5.008, DEFAULT_OFF],
			     	'parenthesis'	=> [ 5.008, DEFAULT_OFF],
       	 			'printf'	=> [ 5.008, DEFAULT_OFF],
       	 			'prototype'	=> [ 5.008, DEFAULT_OFF],
       	 			'qw'		=> [ 5.008, DEFAULT_OFF],
			   }],
       	'severe'	=> [ 5.008, { 	
				'inplace'	=> [ 5.008, DEFAULT_ON],
	 			'internal'	=> [ 5.008, DEFAULT_ON],
         			'debugging'	=> [ 5.008, DEFAULT_ON],
         			'malloc'	=> [ 5.008, DEFAULT_ON],
	 		   }],
        'deprecated'	=> [ 5.008, DEFAULT_OFF],
       	'void'		=> [ 5.008, DEFAULT_OFF],
       	'recursion'	=> [ 5.008, DEFAULT_OFF],
       	'redefine'	=> [ 5.008, DEFAULT_OFF],
       	'numeric'	=> [ 5.008, DEFAULT_OFF],
        'uninitialized'	=> [ 5.008, DEFAULT_OFF],
       	'once'		=> [ 5.008, DEFAULT_OFF],
       	'misc'		=> [ 5.008, DEFAULT_OFF],
       	'regexp'	=> [ 5.008, DEFAULT_OFF],
       	'glob'		=> [ 5.008, DEFAULT_OFF],
       	'untie'		=> [ 5.008, DEFAULT_OFF],
	'substr'	=> [ 5.008, DEFAULT_OFF],
	'taint'		=> [ 5.008, DEFAULT_OFF],
	'signal'	=> [ 5.008, DEFAULT_OFF],
	'closure'	=> [ 5.008, DEFAULT_OFF],
	'overflow'	=> [ 5.008, DEFAULT_OFF],
	'portable'	=> [ 5.008, DEFAULT_OFF],
	'utf8'		=> [ 5.008, DEFAULT_OFF],
       	'exiting'	=> [ 5.008, DEFAULT_OFF],
       	'pack'		=> [ 5.008, DEFAULT_OFF],
       	'unpack'	=> [ 5.008, DEFAULT_OFF],
       	'threads'	=> [ 5.008, DEFAULT_OFF],

       	 #'default'	=> [ 5.008, DEFAULT_ON ],
  	}],
} ;

###########################################################################
sub tab {
    my($l, $t) = @_;
    $t .= "\t" x ($l - (length($t) + 1) / 8);
    $t;
}

###########################################################################

my %list ;
my %Value ;
my %ValueToName ;
my %NameToValue ;
my $index ;

my %v_list = () ;

sub valueWalk
{
    my $tre = shift ;
    my @list = () ;
    my ($k, $v) ;

    foreach $k (sort keys %$tre) {
	$v = $tre->{$k};
	die "duplicate key $k\n" if defined $list{$k} ;
	die "Value associated with key '$k' is not an ARRAY reference"
	    if !ref $v || ref $v ne 'ARRAY' ;

	my ($ver, $rest) = @{ $v } ;
	push @{ $v_list{$ver} }, $k;
	
	if (ref $rest)
	  { valueWalk ($rest) }

    }

}

sub orderValues
{
    my $index = 0;
    foreach my $ver ( sort { $a <=> $b } keys %v_list ) {
        foreach my $name (@{ $v_list{$ver} } ) {
	    $ValueToName{ $index } = [ uc $name, $ver ] ;
	    $NameToValue{ uc $name } = $index ++ ;
        }
    }

    return $index ;
}

###########################################################################

sub walk
{
    my $tre = shift ;
    my @list = () ;
    my ($k, $v) ;

    foreach $k (sort keys %$tre) {
	$v = $tre->{$k};
	die "duplicate key $k\n" if defined $list{$k} ;
	#$Value{$index} = uc $k ;
	die "Can't find key '$k'"
	    if ! defined $NameToValue{uc $k} ;
        push @{ $list{$k} }, $NameToValue{uc $k} ;
	die "Value associated with key '$k' is not an ARRAY reference"
	    if !ref $v || ref $v ne 'ARRAY' ;
	
	my ($ver, $rest) = @{ $v } ;
	if (ref $rest)
	  { push (@{ $list{$k} }, walk ($rest)) }

	push @list, @{ $list{$k} } ;
    }

   return @list ;
}

###########################################################################

sub mkRange
{
    my @a = @_ ;
    my @out = @a ;
    my $i ;


    for ($i = 1 ; $i < @a; ++ $i) {
      	$out[$i] = ".."
          if $a[$i] == $a[$i - 1] + 1 && $a[$i] + 1 == $a[$i + 1] ;
    }

    my $out = join(",",@out);

    $out =~ s/,(\.\.,)+/../g ;
    return $out;
}

###########################################################################
sub printTree
{
    my $tre = shift ;
    my $prefix = shift ;
    my ($k, $v) ;

    my $max = (sort {$a <=> $b} map { length $_ } keys %$tre)[-1] ;
    my @keys = sort keys %$tre ;

    while ($k = shift @keys) {
	$v = $tre->{$k};
	die "Value associated with key '$k' is not an ARRAY reference"
	    if !ref $v || ref $v ne 'ARRAY' ;
	
        my $offset ;
	if ($tre ne $tree) {
	    print $prefix . "|\n" ;
	    print $prefix . "+- $k" ;
	    $offset = ' ' x ($max + 4) ;
	}
	else {
	    print $prefix . "$k" ;
	    $offset = ' ' x ($max + 1) ;
	}

	my ($ver, $rest) = @{ $v } ;
	if (ref $rest)
	{
	    my $bar = @keys ? "|" : " ";
	    print " -" . "-" x ($max - length $k ) . "+\n" ;
	    printTree ($rest, $prefix . $bar . $offset )
	}
	else
	  { print "\n" }
    }

}

###########################################################################

sub mkHexOct
{
    my ($f, $max, @a) = @_ ;
    my $mask = "\x00" x $max ;
    my $string = "" ;

    foreach (@a) {
	vec($mask, $_, 1) = 1 ;
    }

    foreach (unpack("C*", $mask)) {
        if ($f eq 'x') {
            $string .= '\x' . sprintf("%2.2x", $_)
        }
        else {
            $string .= '\\' . sprintf("%o", $_)
        }
    }
    return $string ;
}

sub mkHex
{
    my($max, @a) = @_;
    return mkHexOct("x", $max, @a);
}

sub mkOct
{
    my($max, @a) = @_;
    return mkHexOct("o", $max, @a);
}

###########################################################################

if (@ARGV && $ARGV[0] eq "tree")
{
    printTree($tree, "    ") ;
    exit ;
}

my $warn = safer_open("warnings.h-new");
my $pm = safer_open("lib/warnings.pm-new");

print $warn <<'EOM' ;
/* -*- buffer-read-only: t -*-
   !!!!!!!   DO NOT EDIT THIS FILE   !!!!!!!
   This file is built by warnings.pl
   Any changes made here will be lost!
*/


#define Off(x)			((x) / 8)
#define Bit(x)			(1 << ((x) % 8))
#define IsSet(a, x)		((a)[Off(x)] & Bit(x))


#define G_WARN_OFF		0 	/* $^W == 0 */
#define G_WARN_ON		1	/* -w flag and $^W != 0 */
#define G_WARN_ALL_ON		2	/* -W flag */
#define G_WARN_ALL_OFF		4	/* -X flag */
#define G_WARN_ONCE		8	/* set if 'once' ever enabled */
#define G_WARN_ALL_MASK		(G_WARN_ALL_ON|G_WARN_ALL_OFF)

#define pWARN_STD		NULL
#define pWARN_ALL		(((STRLEN*)0)+1)    /* use warnings 'all' */
#define pWARN_NONE		(((STRLEN*)0)+2)    /* no  warnings 'all' */

#define specialWARN(x)		((x) == pWARN_STD || (x) == pWARN_ALL ||	\
				 (x) == pWARN_NONE)

/* if PL_warnhook is set to this value, then warnings die */
#define PERL_WARNHOOK_FATAL	(&PL_sv_placeholder)
EOM

my $offset = 0 ;

$index = $offset ;
#@{ $list{"all"} } = walk ($tree) ;
valueWalk ($tree) ;
my $index = orderValues();

die <<EOM if $index > 255 ;
Too many warnings categories -- max is 255
    rewrite packWARN* & unpackWARN* macros 
EOM

walk ($tree) ;

$index *= 2 ;
my $warn_size = int($index / 8) + ($index % 8 != 0) ;

my $k ;
my $last_ver = 0;
foreach $k (sort { $a <=> $b } keys %ValueToName) {
    my ($name, $version) = @{ $ValueToName{$k} };
    print $warn "\n/* Warnings Categories added in Perl $version */\n\n"
        if $last_ver != $version ;
    print $warn tab(5, "#define WARN_$name"), "$k\n" ;
    $last_ver = $version ;
}
print $warn "\n" ;

print $warn tab(5, '#define WARNsize'),	"$warn_size\n" ;
#print WARN tab(5, '#define WARN_ALLstring'), '"', ('\377' x $warn_size) , "\"\n" ;
print $warn tab(5, '#define WARN_ALLstring'), '"', ('\125' x $warn_size) , "\"\n" ;
print $warn tab(5, '#define WARN_NONEstring'), '"', ('\0' x $warn_size) , "\"\n" ;

print $warn <<'EOM';

#define isLEXWARN_on 	(PL_curcop->cop_warnings != pWARN_STD)
#define isLEXWARN_off	(PL_curcop->cop_warnings == pWARN_STD)
#define isWARN_ONCE	(PL_dowarn & (G_WARN_ON|G_WARN_ONCE))
#define isWARN_on(c,x)	(IsSet((U8 *)(c + 1), 2*(x)))
#define isWARNf_on(c,x)	(IsSet((U8 *)(c + 1), 2*(x)+1))

#define DUP_WARNINGS(p)		\
    (specialWARN(p) ? (STRLEN*)(p)	\
    : (STRLEN*)CopyD(p, PerlMemShared_malloc(sizeof(*p)+*p), sizeof(*p)+*p, \
		     			     char))

#define ckWARN(w)		Perl_ckwarn(aTHX_ packWARN(w))
#define ckWARN2(w1,w2)		Perl_ckwarn(aTHX_ packWARN2(w1,w2))
#define ckWARN3(w1,w2,w3)	Perl_ckwarn(aTHX_ packWARN3(w1,w2,w3))
#define ckWARN4(w1,w2,w3,w4)	Perl_ckwarn(aTHX_ packWARN4(w1,w2,w3,w4))

#define ckWARN_d(w)		Perl_ckwarn_d(aTHX_ packWARN(w))
#define ckWARN2_d(w1,w2)	Perl_ckwarn_d(aTHX_ packWARN2(w1,w2))
#define ckWARN3_d(w1,w2,w3)	Perl_ckwarn_d(aTHX_ packWARN3(w1,w2,w3))
#define ckWARN4_d(w1,w2,w3,w4)	Perl_ckwarn_d(aTHX_ packWARN4(w1,w2,w3,w4))

#define packWARN(a)		(a                                      )
#define packWARN2(a,b)		((a) | ((b)<<8)                         )
#define packWARN3(a,b,c)	((a) | ((b)<<8) | ((c)<<16)             )
#define packWARN4(a,b,c,d)	((a) | ((b)<<8) | ((c)<<16) | ((d) <<24))

#define unpackWARN1(x)		((x)        & 0xFF)
#define unpackWARN2(x)		(((x) >>8)  & 0xFF)
#define unpackWARN3(x)		(((x) >>16) & 0xFF)
#define unpackWARN4(x)		(((x) >>24) & 0xFF)

#define ckDEAD(x)							\
	   ( ! specialWARN(PL_curcop->cop_warnings) &&			\
	    ( isWARNf_on(PL_curcop->cop_warnings, WARN_ALL) || 		\
	      isWARNf_on(PL_curcop->cop_warnings, unpackWARN1(x)) ||	\
	      isWARNf_on(PL_curcop->cop_warnings, unpackWARN2(x)) ||	\
	      isWARNf_on(PL_curcop->cop_warnings, unpackWARN3(x)) ||	\
	      isWARNf_on(PL_curcop->cop_warnings, unpackWARN4(x))))

/* end of file warnings.h */
/* ex: set ro: */
EOM

safer_close $warn;
rename_if_different("warnings.h-new", "warnings.h");

while (<DATA>) {
    last if /^KEYWORDS$/ ;
    print $pm $_ ;
}

#$list{'all'} = [ $offset .. 8 * ($warn_size/2) - 1 ] ;

$last_ver = 0;
print $pm "our %Offsets = (\n" ;
foreach my $k (sort { $a <=> $b } keys %ValueToName) {
    my ($name, $version) = @{ $ValueToName{$k} };
    $name = lc $name;
    $k *= 2 ;
    if ( $last_ver != $version ) {
        print $pm "\n";
        print $pm tab(4, "    # Warnings Categories added in Perl $version");
        print $pm "\n\n";
    }
    print $pm tab(4, "    '$name'"), "=> $k,\n" ;
    $last_ver = $version;
}

print $pm "  );\n\n" ;

print $pm "our %Bits = (\n" ;
foreach $k (sort keys  %list) {

    my $v = $list{$k} ;
    my @list = sort { $a <=> $b } @$v ;

    print $pm tab(4, "    '$k'"), '=> "',
		# mkHex($warn_size, @list),
		mkHex($warn_size, map $_ * 2 , @list),
		'", # [', mkRange(@list), "]\n" ;
}

print $pm "  );\n\n" ;

print $pm "our %DeadBits = (\n" ;
foreach $k (sort keys  %list) {

    my $v = $list{$k} ;
    my @list = sort { $a <=> $b } @$v ;

    print $pm tab(4, "    '$k'"), '=> "',
		# mkHex($warn_size, @list),
		mkHex($warn_size, map $_ * 2 + 1 , @list),
		'", # [', mkRange(@list), "]\n" ;
}

print $pm "  );\n\n" ;
print $pm '$NONE     = "', ('\0' x $warn_size) , "\";\n" ;
print $pm '$LAST_BIT = ' . "$index ;\n" ;
print $pm '$BYTES    = ' . "$warn_size ;\n" ;
while (<DATA>) {
    print $pm $_ ;
}

print $pm "# ex: set ro:\n";
safer_close $pm;
rename_if_different("lib/warnings.pm-new", "lib/warnings.pm");

__END__
# -*- buffer-read-only: t -*-
# !!!!!!!   DO NOT EDIT THIS FILE   !!!!!!!
# This file was created by warnings.pl
# Any changes made here will be lost.
#

package warnings;

our $VERSION = '1.06';

# Verify that we're called correctly so that warnings will work.
# see also strict.pm.
unless ( __FILE__ =~ /(^|[\/\\])\Q${\__PACKAGE__}\E\.pmc?$/ ) {
    my (undef, $f, $l) = caller;
    die("Incorrect use of pragma '${\__PACKAGE__}' at $f line $l.\n");
}

=head1 NAME

warnings - Perl pragma to control optional warnings

=head1 SYNOPSIS

    use warnings;
    no warnings;

    use warnings "all";
    no warnings "all";

    use warnings::register;
    if (warnings::enabled()) {
        warnings::warn("some warning");
    }

    if (warnings::enabled("void")) {
        warnings::warn("void", "some warning");
    }

    if (warnings::enabled($object)) {
        warnings::warn($object, "some warning");
    }

    warnings::warnif("some warning");
    warnings::warnif("void", "some warning");
    warnings::warnif($object, "some warning");

=head1 DESCRIPTION

The C<warnings> pragma is a replacement for the command line flag C<-w>,
but the pragma is limited to the enclosing block, while the flag is global.
See L<perllexwarn> for more information.

If no import list is supplied, all possible warnings are either enabled
or disabled.

A number of functions are provided to assist module authors.

=over 4

=item use warnings::register

Creates a new warnings category with the same name as the package where
the call to the pragma is used.

=item warnings::enabled()

Use the warnings category with the same name as the current package.

Return TRUE if that warnings category is enabled in the calling module.
Otherwise returns FALSE.

=item warnings::enabled($category)

Return TRUE if the warnings category, C<$category>, is enabled in the
calling module.
Otherwise returns FALSE.

=item warnings::enabled($object)

Use the name of the class for the object reference, C<$object>, as the
warnings category.

Return TRUE if that warnings category is enabled in the first scope
where the object is used.
Otherwise returns FALSE.

=item warnings::warn($message)

Print C<$message> to STDERR.

Use the warnings category with the same name as the current package.

If that warnings category has been set to "FATAL" in the calling module
then die. Otherwise return.

=item warnings::warn($category, $message)

Print C<$message> to STDERR.

If the warnings category, C<$category>, has been set to "FATAL" in the
calling module then die. Otherwise return.

=item warnings::warn($object, $message)

Print C<$message> to STDERR.

Use the name of the class for the object reference, C<$object>, as the
warnings category.

If that warnings category has been set to "FATAL" in the scope where C<$object>
is first used then die. Otherwise return.


=item warnings::warnif($message)

Equivalent to:

    if (warnings::enabled())
      { warnings::warn($message) }

=item warnings::warnif($category, $message)

Equivalent to:

    if (warnings::enabled($category))
      { warnings::warn($category, $message) }

=item warnings::warnif($object, $message)

Equivalent to:

    if (warnings::enabled($object))
      { warnings::warn($object, $message) }

=back

See L<perlmodlib/Pragmatic Modules> and L<perllexwarn>.

=cut

KEYWORDS

$All = "" ; vec($All, $Offsets{'all'}, 2) = 3 ;

sub Croaker
{
    require Carp::Heavy; # this initializes %CarpInternal
    local $Carp::CarpInternal{'warnings'};
    delete $Carp::CarpInternal{'warnings'};
    Carp::croak(@_);
}

sub bits
{
    # called from B::Deparse.pm

    push @_, 'all' unless @_;

    my $mask;
    my $catmask ;
    my $fatal = 0 ;
    my $no_fatal = 0 ;

    foreach my $word ( @_ ) {
	if ($word eq 'FATAL') {
	    $fatal = 1;
	    $no_fatal = 0;
	}
	elsif ($word eq 'NONFATAL') {
	    $fatal = 0;
	    $no_fatal = 1;
	}
	elsif ($catmask = $Bits{$word}) {
	    $mask |= $catmask ;
	    $mask |= $DeadBits{$word} if $fatal ;
	    $mask &= ~($DeadBits{$word}|$All) if $no_fatal ;
	}
	else
          { Croaker("Unknown warnings category '$word'")}
    }

    return $mask ;
}

sub import 
{
    shift;

    my $catmask ;
    my $fatal = 0 ;
    my $no_fatal = 0 ;

    my $mask = ${^WARNING_BITS} ;

    if (vec($mask, $Offsets{'all'}, 1)) {
        $mask |= $Bits{'all'} ;
        $mask |= $DeadBits{'all'} if vec($mask, $Offsets{'all'}+1, 1);
    }
    
    push @_, 'all' unless @_;

    foreach my $word ( @_ ) {
	if ($word eq 'FATAL') {
	    $fatal = 1;
	    $no_fatal = 0;
	}
	elsif ($word eq 'NONFATAL') {
	    $fatal = 0;
	    $no_fatal = 1;
	}
	elsif ($catmask = $Bits{$word}) {
	    $mask |= $catmask ;
	    $mask |= $DeadBits{$word} if $fatal ;
	    $mask &= ~($DeadBits{$word}|$All) if $no_fatal ;
	}
	else
          { Croaker("Unknown warnings category '$word'")}
    }

    ${^WARNING_BITS} = $mask ;
}

sub unimport 
{
    shift;

    my $catmask ;
    my $mask = ${^WARNING_BITS} ;

    if (vec($mask, $Offsets{'all'}, 1)) {
        $mask |= $Bits{'all'} ;
        $mask |= $DeadBits{'all'} if vec($mask, $Offsets{'all'}+1, 1);
    }

    push @_, 'all' unless @_;

    foreach my $word ( @_ ) {
	if ($word eq 'FATAL') {
	    next; 
	}
	elsif ($catmask = $Bits{$word}) {
	    $mask &= ~($catmask | $DeadBits{$word} | $All);
	}
	else
          { Croaker("Unknown warnings category '$word'")}
    }

    ${^WARNING_BITS} = $mask ;
}

my %builtin_type; @builtin_type{qw(SCALAR ARRAY HASH CODE REF GLOB LVALUE Regexp)} = ();

sub __chk
{
    my $category ;
    my $offset ;
    my $isobj = 0 ;

    if (@_) {
        # check the category supplied.
        $category = shift ;
        if (my $type = ref $category) {
            Croaker("not an object")
                if exists $builtin_type{$type};
	    $category = $type;
            $isobj = 1 ;
        }
        $offset = $Offsets{$category};
        Croaker("Unknown warnings category '$category'")
	    unless defined $offset;
    }
    else {
        $category = (caller(1))[0] ;
        $offset = $Offsets{$category};
        Croaker("package '$category' not registered for warnings")
	    unless defined $offset ;
    }

    my $this_pkg = (caller(1))[0] ;
    my $i = 2 ;
    my $pkg ;

    if ($isobj) {
        while (do { { package DB; $pkg = (caller($i++))[0] } } ) {
            last unless @DB::args && $DB::args[0] =~ /^$category=/ ;
        }
	$i -= 2 ;
    }
    else {
        $i = _error_loc(); # see where Carp will allocate the error
    }

    my $callers_bitmask = (caller($i))[9] ;
    return ($callers_bitmask, $offset, $i) ;
}

sub _error_loc {
    require Carp::Heavy;
    goto &Carp::short_error_loc; # don't introduce another stack frame
}                                                             

sub enabled
{
    Croaker("Usage: warnings::enabled([category])")
	unless @_ == 1 || @_ == 0 ;

    my ($callers_bitmask, $offset, $i) = __chk(@_) ;

    return 0 unless defined $callers_bitmask ;
    return vec($callers_bitmask, $offset, 1) ||
           vec($callers_bitmask, $Offsets{'all'}, 1) ;
}


sub warn
{
    Croaker("Usage: warnings::warn([category,] 'message')")
	unless @_ == 2 || @_ == 1 ;

    my $message = pop ;
    my ($callers_bitmask, $offset, $i) = __chk(@_) ;
    require Carp;
    Carp::croak($message)
	if vec($callers_bitmask, $offset+1, 1) ||
	   vec($callers_bitmask, $Offsets{'all'}+1, 1) ;
    Carp::carp($message) ;
}

sub warnif
{
    Croaker("Usage: warnings::warnif([category,] 'message')")
	unless @_ == 2 || @_ == 1 ;

    my $message = pop ;
    my ($callers_bitmask, $offset, $i) = __chk(@_) ;

    return
        unless defined $callers_bitmask &&
            	(vec($callers_bitmask, $offset, 1) ||
            	vec($callers_bitmask, $Offsets{'all'}, 1)) ;

    require Carp;
    Carp::croak($message)
	if vec($callers_bitmask, $offset+1, 1) ||
	   vec($callers_bitmask, $Offsets{'all'}+1, 1) ;

    Carp::carp($message) ;
}

1;