This is a live mirror of the Perl 5 development currently hosted at https://github.com/perl/perl5
Increase $feature::VERSION to 1.40
[perl5.git] / lib / warnings.pm
CommitLineData
37442d52 1# -*- buffer-read-only: t -*-
38875929 2# !!!!!!! DO NOT EDIT THIS FILE !!!!!!!
78102347
NC
3# This file is built by regen/warnings.pl.
4# Any changes made here will be lost!
599cee73 5
4438c4b7 6package warnings;
599cee73 7
3c3f8cd6 8our $VERSION = '1.31';
f2c3e829
RGS
9
10# Verify that we're called correctly so that warnings will work.
11# see also strict.pm.
5108dc18 12unless ( __FILE__ =~ /(^|[\/\\])\Q${\__PACKAGE__}\E\.pmc?$/ ) {
f2c3e829 13 my (undef, $f, $l) = caller;
5108dc18 14 die("Incorrect use of pragma '${\__PACKAGE__}' at $f line $l.\n");
f2c3e829 15}
0ca4541c 16
effd17dc 17our %Offsets = (
effd17dc 18 # Warnings Categories added in Perl 5.008
3c3f8cd6
AB
19 'all' => 0,
20 'closure' => 2,
21 'deprecated' => 4,
22 'exiting' => 6,
23 'glob' => 8,
24 'io' => 10,
25 'closed' => 12,
26 'exec' => 14,
27 'layer' => 16,
28 'newline' => 18,
29 'pipe' => 20,
30 'unopened' => 22,
31 'misc' => 24,
32 'numeric' => 26,
33 'once' => 28,
34 'overflow' => 30,
35 'pack' => 32,
36 'portable' => 34,
37 'recursion' => 36,
38 'redefine' => 38,
39 'regexp' => 40,
40 'severe' => 42,
41 'debugging' => 44,
42 'inplace' => 46,
43 'internal' => 48,
44 'malloc' => 50,
45 'signal' => 52,
46 'substr' => 54,
47 'syntax' => 56,
48 'ambiguous' => 58,
49 'bareword' => 60,
50 'digit' => 62,
51 'parenthesis' => 64,
52 'precedence' => 66,
53 'printf' => 68,
54 'prototype' => 70,
55 'qw' => 72,
56 'reserved' => 74,
57 'semicolon' => 76,
58 'taint' => 78,
59 'threads' => 80,
60 'uninitialized' => 82,
61 'unpack' => 84,
62 'untie' => 86,
63 'utf8' => 88,
64 'void' => 90,
effd17dc
DD
65
66 # Warnings Categories added in Perl 5.011
3c3f8cd6
AB
67 'imprecision' => 92,
68 'illegalproto' => 94,
effd17dc
DD
69
70 # Warnings Categories added in Perl 5.013
3c3f8cd6
AB
71 'non_unicode' => 96,
72 'nonchar' => 98,
73 'surrogate' => 100,
effd17dc
DD
74
75 # Warnings Categories added in Perl 5.017
3c3f8cd6
AB
76 'experimental' => 102,
77 'experimental::lexical_subs' => 104,
78 'experimental::lexical_topic' => 106,
79 'experimental::regex_sets' => 108,
80 'experimental::smartmatch' => 110,
effd17dc
DD
81
82 # Warnings Categories added in Perl 5.019
3c3f8cd6
AB
83 'experimental::autoderef' => 112,
84 'experimental::postderef' => 114,
85 'experimental::signatures' => 116,
86 'syscalls' => 118,
effd17dc
DD
87
88 # Warnings Categories added in Perl 5.021
3c3f8cd6
AB
89 'experimental::const_attr' => 120,
90 'experimental::re_strict' => 122,
91 'experimental::refaliasing' => 124,
92 'experimental::win32_perlio' => 126,
93 'locale' => 128,
94 'missing' => 130,
95 'redundant' => 132,
96);
effd17dc
DD
97
98our %Bits = (
3c3f8cd6
AB
99 'all' => "\x55\x55\x55\x55\x55\x55\x55\x55\x55\x55\x55\x55\x55\x55\x55\x55\x15", # [0..66]
100 'ambiguous' => "\x00\x00\x00\x00\x00\x00\x00\x04\x00\x00\x00\x00\x00\x00\x00\x00\x00", # [29]
101 'bareword' => "\x00\x00\x00\x00\x00\x00\x00\x10\x00\x00\x00\x00\x00\x00\x00\x00\x00", # [30]
102 'closed' => "\x00\x10\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00", # [6]
103 'closure' => "\x04\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00", # [1]
104 'debugging' => "\x00\x00\x00\x00\x00\x10\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00", # [22]
105 'deprecated' => "\x10\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00", # [2]
106 'digit' => "\x00\x00\x00\x00\x00\x00\x00\x40\x00\x00\x00\x00\x00\x00\x00\x00\x00", # [31]
107 'exec' => "\x00\x40\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00", # [7]
108 'exiting' => "\x40\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00", # [3]
109 'experimental' => "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x40\x55\x15\x55\x00", # [51..58,60..63]
110 'experimental::autoderef' => "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x01\x00\x00", # [56]
111 'experimental::const_attr' => "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x01\x00", # [60]
112 'experimental::lexical_subs' => "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x01\x00\x00\x00", # [52]
113 'experimental::lexical_topic' => "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x04\x00\x00\x00", # [53]
114 'experimental::postderef' => "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x04\x00\x00", # [57]
115 'experimental::re_strict' => "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x04\x00", # [61]
116 'experimental::refaliasing' => "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x10\x00", # [62]
117 'experimental::regex_sets' => "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x10\x00\x00\x00", # [54]
118 'experimental::signatures' => "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x10\x00\x00", # [58]
119 'experimental::smartmatch' => "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x40\x00\x00\x00", # [55]
120 'experimental::win32_perlio' => "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x40\x00", # [63]
121 'glob' => "\x00\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00", # [4]
122 'illegalproto' => "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x40\x00\x00\x00\x00\x00", # [47]
123 'imprecision' => "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x10\x00\x00\x00\x00\x00", # [46]
124 'inplace' => "\x00\x00\x00\x00\x00\x40\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00", # [23]
125 'internal' => "\x00\x00\x00\x00\x00\x00\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00", # [24]
126 'io' => "\x00\x54\x55\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x40\x00\x00", # [5..11,59]
127 'layer' => "\x00\x00\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00", # [8]
128 'locale' => "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x01", # [64]
129 'malloc' => "\x00\x00\x00\x00\x00\x00\x04\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00", # [25]
130 'misc' => "\x00\x00\x00\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00", # [12]
131 'missing' => "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x04", # [65]
132 'newline' => "\x00\x00\x04\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00", # [9]
133 'non_unicode' => "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x01\x00\x00\x00\x00", # [48]
134 'nonchar' => "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x04\x00\x00\x00\x00", # [49]
135 'numeric' => "\x00\x00\x00\x04\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00", # [13]
136 'once' => "\x00\x00\x00\x10\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00", # [14]
137 'overflow' => "\x00\x00\x00\x40\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00", # [15]
138 'pack' => "\x00\x00\x00\x00\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00", # [16]
139 'parenthesis' => "\x00\x00\x00\x00\x00\x00\x00\x00\x01\x00\x00\x00\x00\x00\x00\x00\x00", # [32]
140 'pipe' => "\x00\x00\x10\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00", # [10]
141 'portable' => "\x00\x00\x00\x00\x04\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00", # [17]
142 'precedence' => "\x00\x00\x00\x00\x00\x00\x00\x00\x04\x00\x00\x00\x00\x00\x00\x00\x00", # [33]
143 'printf' => "\x00\x00\x00\x00\x00\x00\x00\x00\x10\x00\x00\x00\x00\x00\x00\x00\x00", # [34]
144 'prototype' => "\x00\x00\x00\x00\x00\x00\x00\x00\x40\x00\x00\x00\x00\x00\x00\x00\x00", # [35]
145 'qw' => "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x01\x00\x00\x00\x00\x00\x00\x00", # [36]
146 'recursion' => "\x00\x00\x00\x00\x10\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00", # [18]
147 'redefine' => "\x00\x00\x00\x00\x40\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00", # [19]
148 'redundant' => "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x10", # [66]
149 'regexp' => "\x00\x00\x00\x00\x00\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00", # [20]
150 'reserved' => "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x04\x00\x00\x00\x00\x00\x00\x00", # [37]
151 'semicolon' => "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x10\x00\x00\x00\x00\x00\x00\x00", # [38]
152 'severe' => "\x00\x00\x00\x00\x00\x54\x05\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00", # [21..25]
153 'signal' => "\x00\x00\x00\x00\x00\x00\x10\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00", # [26]
154 'substr' => "\x00\x00\x00\x00\x00\x00\x40\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00", # [27]
155 'surrogate' => "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x10\x00\x00\x00\x00", # [50]
156 'syntax' => "\x00\x00\x00\x00\x00\x00\x00\x55\x55\x15\x00\x40\x00\x00\x00\x00\x00", # [28..38,47]
157 'syscalls' => "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x40\x00\x00", # [59]
158 'taint' => "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x40\x00\x00\x00\x00\x00\x00\x00", # [39]
159 'threads' => "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x01\x00\x00\x00\x00\x00\x00", # [40]
160 'uninitialized' => "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x04\x00\x00\x00\x00\x00\x00", # [41]
161 'unopened' => "\x00\x00\x40\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00", # [11]
162 'unpack' => "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x10\x00\x00\x00\x00\x00\x00", # [42]
163 'untie' => "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x40\x00\x00\x00\x00\x00\x00", # [43]
164 'utf8' => "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x01\x15\x00\x00\x00\x00", # [44,48..50]
165 'void' => "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x04\x00\x00\x00\x00\x00", # [45]
166);
effd17dc
DD
167
168our %DeadBits = (
3c3f8cd6
AB
169 'all' => "\xaa\xaa\xaa\xaa\xaa\xaa\xaa\xaa\xaa\xaa\xaa\xaa\xaa\xaa\xaa\xaa\x2a", # [0..66]
170 'ambiguous' => "\x00\x00\x00\x00\x00\x00\x00\x08\x00\x00\x00\x00\x00\x00\x00\x00\x00", # [29]
171 'bareword' => "\x00\x00\x00\x00\x00\x00\x00\x20\x00\x00\x00\x00\x00\x00\x00\x00\x00", # [30]
172 'closed' => "\x00\x20\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00", # [6]
173 'closure' => "\x08\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00", # [1]
174 'debugging' => "\x00\x00\x00\x00\x00\x20\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00", # [22]
175 'deprecated' => "\x20\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00", # [2]
176 'digit' => "\x00\x00\x00\x00\x00\x00\x00\x80\x00\x00\x00\x00\x00\x00\x00\x00\x00", # [31]
177 'exec' => "\x00\x80\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00", # [7]
178 'exiting' => "\x80\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00", # [3]
179 'experimental' => "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x80\xaa\x2a\xaa\x00", # [51..58,60..63]
180 'experimental::autoderef' => "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x00", # [56]
181 'experimental::const_attr' => "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00", # [60]
182 'experimental::lexical_subs' => "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x00\x00", # [52]
183 'experimental::lexical_topic' => "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x08\x00\x00\x00", # [53]
184 'experimental::postderef' => "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x08\x00\x00", # [57]
185 'experimental::re_strict' => "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x08\x00", # [61]
186 'experimental::refaliasing' => "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x20\x00", # [62]
187 'experimental::regex_sets' => "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x20\x00\x00\x00", # [54]
188 'experimental::signatures' => "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x20\x00\x00", # [58]
189 'experimental::smartmatch' => "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x80\x00\x00\x00", # [55]
190 'experimental::win32_perlio' => "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x80\x00", # [63]
191 'glob' => "\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00", # [4]
192 'illegalproto' => "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x80\x00\x00\x00\x00\x00", # [47]
193 'imprecision' => "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x20\x00\x00\x00\x00\x00", # [46]
194 'inplace' => "\x00\x00\x00\x00\x00\x80\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00", # [23]
195 'internal' => "\x00\x00\x00\x00\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00", # [24]
196 'io' => "\x00\xa8\xaa\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x80\x00\x00", # [5..11,59]
197 'layer' => "\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00", # [8]
198 'locale' => "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02", # [64]
199 'malloc' => "\x00\x00\x00\x00\x00\x00\x08\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00", # [25]
200 'misc' => "\x00\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00", # [12]
201 'missing' => "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x08", # [65]
202 'newline' => "\x00\x00\x08\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00", # [9]
203 'non_unicode' => "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x00\x00\x00", # [48]
204 'nonchar' => "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x08\x00\x00\x00\x00", # [49]
205 'numeric' => "\x00\x00\x00\x08\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00", # [13]
206 'once' => "\x00\x00\x00\x20\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00", # [14]
207 'overflow' => "\x00\x00\x00\x80\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00", # [15]
208 'pack' => "\x00\x00\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00", # [16]
209 'parenthesis' => "\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00", # [32]
210 'pipe' => "\x00\x00\x20\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00", # [10]
211 'portable' => "\x00\x00\x00\x00\x08\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00", # [17]
212 'precedence' => "\x00\x00\x00\x00\x00\x00\x00\x00\x08\x00\x00\x00\x00\x00\x00\x00\x00", # [33]
213 'printf' => "\x00\x00\x00\x00\x00\x00\x00\x00\x20\x00\x00\x00\x00\x00\x00\x00\x00", # [34]
214 'prototype' => "\x00\x00\x00\x00\x00\x00\x00\x00\x80\x00\x00\x00\x00\x00\x00\x00\x00", # [35]
215 'qw' => "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00", # [36]
216 'recursion' => "\x00\x00\x00\x00\x20\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00", # [18]
217 'redefine' => "\x00\x00\x00\x00\x80\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00", # [19]
218 'redundant' => "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x20", # [66]
219 'regexp' => "\x00\x00\x00\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00", # [20]
220 'reserved' => "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x08\x00\x00\x00\x00\x00\x00\x00", # [37]
221 'semicolon' => "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x20\x00\x00\x00\x00\x00\x00\x00", # [38]
222 'severe' => "\x00\x00\x00\x00\x00\xa8\x0a\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00", # [21..25]
223 'signal' => "\x00\x00\x00\x00\x00\x00\x20\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00", # [26]
224 'substr' => "\x00\x00\x00\x00\x00\x00\x80\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00", # [27]
225 'surrogate' => "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x20\x00\x00\x00\x00", # [50]
226 'syntax' => "\x00\x00\x00\x00\x00\x00\x00\xaa\xaa\x2a\x00\x80\x00\x00\x00\x00\x00", # [28..38,47]
227 'syscalls' => "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x80\x00\x00", # [59]
228 'taint' => "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x80\x00\x00\x00\x00\x00\x00\x00", # [39]
229 'threads' => "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x00\x00\x00\x00\x00", # [40]
230 'uninitialized' => "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x08\x00\x00\x00\x00\x00\x00", # [41]
231 'unopened' => "\x00\x00\x80\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00", # [11]
232 'unpack' => "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x20\x00\x00\x00\x00\x00\x00", # [42]
233 'untie' => "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x80\x00\x00\x00\x00\x00\x00", # [43]
234 'utf8' => "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x2a\x00\x00\x00\x00", # [44,48..50]
235 'void' => "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x08\x00\x00\x00\x00\x00", # [45]
236);
237
238# These are used by various things, including our own tests
239our $NONE = "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0";
240our $DEFAULT = "\x10\x01\x00\x00\x00\x50\x04\x00\x00\x00\x00\x00\x00\x55\x15\x55\x01", # [2,56,60,52,53,57,61,62,54,58,55,63,4,64,22,23,25]
241our $LAST_BIT = 134 ;
242our $BYTES = 17 ;
243
244our $All = "" ; vec($All, $Offsets{'all'}, 2) = 3 ;
effd17dc
DD
245
246sub Croaker
247{
248 require Carp; # this initializes %CarpInternal
249 local $Carp::CarpInternal{'warnings'};
250 delete $Carp::CarpInternal{'warnings'};
251 Carp::croak(@_);
252}
253
254sub _bits {
255 my $mask = shift ;
256 my $catmask ;
257 my $fatal = 0 ;
258 my $no_fatal = 0 ;
259
260 foreach my $word ( @_ ) {
261 if ($word eq 'FATAL') {
262 $fatal = 1;
263 $no_fatal = 0;
264 }
265 elsif ($word eq 'NONFATAL') {
266 $fatal = 0;
267 $no_fatal = 1;
268 }
269 elsif ($catmask = $Bits{$word}) {
270 $mask |= $catmask ;
271 $mask |= $DeadBits{$word} if $fatal ;
272 $mask &= ~($DeadBits{$word}|$All) if $no_fatal ;
273 }
274 else
56873d42 275 { Croaker("Unknown warnings category '$word'")}
effd17dc
DD
276 }
277
278 return $mask ;
279}
280
281sub bits
282{
283 # called from B::Deparse.pm
284 push @_, 'all' unless @_ ;
285 return _bits(undef, @_) ;
286}
287
288sub import
289{
290 shift;
291
292 my $mask = ${^WARNING_BITS} // ($^W ? $Bits{all} : $DEFAULT) ;
293
294 if (vec($mask, $Offsets{'all'}, 1)) {
56873d42
DD
295 $mask |= $Bits{'all'} ;
296 $mask |= $DeadBits{'all'} if vec($mask, $Offsets{'all'}+1, 1);
effd17dc
DD
297 }
298
299 # append 'all' when implied (after a lone "FATAL" or "NONFATAL")
300 push @_, 'all' if @_==1 && ( $_[0] eq 'FATAL' || $_[0] eq 'NONFATAL' );
301
302 # Empty @_ is equivalent to @_ = 'all' ;
303 ${^WARNING_BITS} = @_ ? _bits($mask, @_) : $mask | $Bits{all} ;
304}
305
306sub unimport
307{
308 shift;
309
310 my $catmask ;
311 my $mask = ${^WARNING_BITS} // ($^W ? $Bits{all} : $DEFAULT) ;
312
313 if (vec($mask, $Offsets{'all'}, 1)) {
56873d42
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314 $mask |= $Bits{'all'} ;
315 $mask |= $DeadBits{'all'} if vec($mask, $Offsets{'all'}+1, 1);
effd17dc
DD
316 }
317
318 # append 'all' when implied (empty import list or after a lone "FATAL")
319 push @_, 'all' if !@_ || @_==1 && $_[0] eq 'FATAL';
320
321 foreach my $word ( @_ ) {
322 if ($word eq 'FATAL') {
323 next;
324 }
325 elsif ($catmask = $Bits{$word}) {
326 $mask &= ~($catmask | $DeadBits{$word} | $All);
327 }
328 else
56873d42 329 { Croaker("Unknown warnings category '$word'")}
effd17dc
DD
330 }
331
332 ${^WARNING_BITS} = $mask ;
333}
334
335my %builtin_type; @builtin_type{qw(SCALAR ARRAY HASH CODE REF GLOB LVALUE Regexp)} = ();
336
337sub MESSAGE () { 4 };
338sub FATAL () { 2 };
339sub NORMAL () { 1 };
340
341sub __chk
342{
343 my $category ;
344 my $offset ;
345 my $isobj = 0 ;
346 my $wanted = shift;
347 my $has_message = $wanted & MESSAGE;
348
349 unless (@_ == 1 || @_ == ($has_message ? 2 : 0)) {
350 my $sub = (caller 1)[3];
351 my $syntax = $has_message ? "[category,] 'message'" : '[category]';
352 Croaker("Usage: $sub($syntax)");
353 }
354
355 my $message = pop if $has_message;
356
357 if (@_) {
56873d42
DD
358 # check the category supplied.
359 $category = shift ;
360 if (my $type = ref $category) {
361 Croaker("not an object")
362 if exists $builtin_type{$type};
effd17dc 363 $category = $type;
56873d42
DD
364 $isobj = 1 ;
365 }
366 $offset = $Offsets{$category};
367 Croaker("Unknown warnings category '$category'")
effd17dc
DD
368 unless defined $offset;
369 }
370 else {
56873d42
DD
371 $category = (caller(1))[0] ;
372 $offset = $Offsets{$category};
373 Croaker("package '$category' not registered for warnings")
effd17dc
DD
374 unless defined $offset ;
375 }
376
377 my $i;
378
379 if ($isobj) {
56873d42
DD
380 my $pkg;
381 $i = 2;
382 while (do { { package DB; $pkg = (caller($i++))[0] } } ) {
383 last unless @DB::args && $DB::args[0] =~ /^$category=/ ;
384 }
effd17dc
DD
385 $i -= 2 ;
386 }
387 else {
56873d42 388 $i = _error_loc(); # see where Carp will allocate the error
effd17dc
DD
389 }
390
391 # Default to 0 if caller returns nothing. Default to $DEFAULT if it
392 # explicitly returns undef.
393 my(@callers_bitmask) = (caller($i))[9] ;
394 my $callers_bitmask =
395 @callers_bitmask ? $callers_bitmask[0] // $DEFAULT : 0 ;
396
397 my @results;
398 foreach my $type (FATAL, NORMAL) {
399 next unless $wanted & $type;
400
401 push @results, (vec($callers_bitmask, $offset + $type - 1, 1) ||
402 vec($callers_bitmask, $Offsets{'all'} + $type - 1, 1));
403 }
404
405 # &enabled and &fatal_enabled
406 return $results[0] unless $has_message;
407
408 # &warnif, and the category is neither enabled as warning nor as fatal
409 return if $wanted == (NORMAL | FATAL | MESSAGE)
410 && !($results[0] || $results[1]);
411
412 require Carp;
413 Carp::croak($message) if $results[0];
414 # will always get here for &warn. will only get here for &warnif if the
415 # category is enabled
416 Carp::carp($message);
417}
418
419sub _mkMask
420{
421 my ($bit) = @_;
422 my $mask = "";
423
424 vec($mask, $bit, 1) = 1;
425 return $mask;
426}
427
428sub register_categories
429{
430 my @names = @_;
431
432 for my $name (@names) {
433 if (! defined $Bits{$name}) {
434 $Bits{$name} = _mkMask($LAST_BIT);
435 vec($Bits{'all'}, $LAST_BIT, 1) = 1;
436 $Offsets{$name} = $LAST_BIT ++;
437 foreach my $k (keys %Bits) {
438 vec($Bits{$k}, $LAST_BIT, 1) = 0;
439 }
440 $DeadBits{$name} = _mkMask($LAST_BIT);
441 vec($DeadBits{'all'}, $LAST_BIT++, 1) = 1;
442 }
443 }
444}
445
446sub _error_loc {
447 require Carp;
448 goto &Carp::short_error_loc; # don't introduce another stack frame
449}
450
451sub enabled
452{
453 return __chk(NORMAL, @_);
454}
455
456sub fatal_enabled
457{
458 return __chk(FATAL, @_);
459}
460
461sub warn
462{
463 return __chk(FATAL | MESSAGE, @_);
464}
465
466sub warnif
467{
468 return __chk(NORMAL | FATAL | MESSAGE, @_);
469}
470
471# These are not part of any public interface, so we can delete them to save
472# space.
473delete @warnings::{qw(NORMAL FATAL MESSAGE)};
474
4751;
476__END__
599cee73
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477=head1 NAME
478
4438c4b7 479warnings - Perl pragma to control optional warnings
599cee73
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480
481=head1 SYNOPSIS
482
4438c4b7
JH
483 use warnings;
484 no warnings;
599cee73 485
4438c4b7
JH
486 use warnings "all";
487 no warnings "all";
599cee73 488
d3a7d8c7
GS
489 use warnings::register;
490 if (warnings::enabled()) {
491 warnings::warn("some warning");
492 }
493
494 if (warnings::enabled("void")) {
e476b1b5
GS
495 warnings::warn("void", "some warning");
496 }
497
7e6d00f8
PM
498 if (warnings::enabled($object)) {
499 warnings::warn($object, "some warning");
500 }
501
721f911b
PM
502 warnings::warnif("some warning");
503 warnings::warnif("void", "some warning");
504 warnings::warnif($object, "some warning");
7e6d00f8 505
599cee73
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506=head1 DESCRIPTION
507
a7f2b7af
RS
508The C<warnings> pragma gives control over which warnings are enabled in
509which parts of a Perl program. It's a more flexible alternative for
510both the command line flag B<-w> and the equivalent Perl variable,
511C<$^W>.
fe2e802c 512
a7f2b7af
RS
513This pragma works just like the C<strict> pragma.
514This means that the scope of the warning pragma is limited to the
515enclosing block. It also means that the pragma setting will not
516leak across files (via C<use>, C<require> or C<do>). This allows
517authors to independently define the degree of warning checks that will
518be applied to their module.
599cee73 519
a7f2b7af
RS
520By default, optional warnings are disabled, so any legacy code that
521doesn't attempt to control the warnings will work unchanged.
522
3c3f8cd6 523All warnings are enabled in a block by either of these:
a7f2b7af
RS
524
525 use warnings;
526 use warnings 'all';
527
3c3f8cd6 528Similarly all warnings are disabled in a block by either of these:
a7f2b7af
RS
529
530 no warnings;
531 no warnings 'all';
532
533For example, consider the code below:
534
535 use warnings;
536 my @a;
537 {
538 no warnings;
539 my $b = @a[0];
540 }
541 my $c = @a[0];
542
543The code in the enclosing block has warnings enabled, but the inner
544block has them disabled. In this case that means the assignment to the
545scalar C<$c> will trip the C<"Scalar value @a[0] better written as $a[0]">
546warning, but the assignment to the scalar C<$b> will not.
547
548=head2 Default Warnings and Optional Warnings
549
550Before the introduction of lexical warnings, Perl had two classes of
56873d42 551warnings: mandatory and optional.
a7f2b7af
RS
552
553As its name suggests, if your code tripped a mandatory warning, you
554would get a warning whether you wanted it or not.
555For example, the code below would always produce an C<"isn't numeric">
556warning about the "2:".
557
558 my $a = "2:" + 3;
559
560With the introduction of lexical warnings, mandatory warnings now become
561I<default> warnings. The difference is that although the previously
562mandatory warnings are still enabled by default, they can then be
563subsequently enabled or disabled with the lexical warning pragma. For
564example, in the code below, an C<"isn't numeric"> warning will only
565be reported for the C<$a> variable.
566
567 my $a = "2:" + 3;
568 no warnings;
569 my $b = "2:" + 3;
570
571Note that neither the B<-w> flag or the C<$^W> can be used to
572disable/enable default warnings. They are still mandatory in this case.
573
574=head2 What's wrong with B<-w> and C<$^W>
575
576Although very useful, the big problem with using B<-w> on the command
577line to enable warnings is that it is all or nothing. Take the typical
578scenario when you are writing a Perl program. Parts of the code you
579will write yourself, but it's very likely that you will make use of
580pre-written Perl modules. If you use the B<-w> flag in this case, you
581end up enabling warnings in pieces of code that you haven't written.
582
583Similarly, using C<$^W> to either disable or enable blocks of code is
584fundamentally flawed. For a start, say you want to disable warnings in
585a block of code. You might expect this to be enough to do the trick:
586
587 {
588 local ($^W) = 0;
589 my $a =+ 2;
590 my $b; chop $b;
591 }
592
593When this code is run with the B<-w> flag, a warning will be produced
594for the C<$a> line: C<"Reversed += operator">.
595
596The problem is that Perl has both compile-time and run-time warnings. To
597disable compile-time warnings you need to rewrite the code like this:
598
599 {
600 BEGIN { $^W = 0 }
601 my $a =+ 2;
602 my $b; chop $b;
603 }
604
605The other big problem with C<$^W> is the way you can inadvertently
606change the warning setting in unexpected places in your code. For example,
607when the code below is run (without the B<-w> flag), the second call
608to C<doit> will trip a C<"Use of uninitialized value"> warning, whereas
609the first will not.
610
611 sub doit
612 {
613 my $b; chop $b;
614 }
615
616 doit();
617
618 {
619 local ($^W) = 1;
620 doit()
621 }
622
623This is a side-effect of C<$^W> being dynamically scoped.
624
625Lexical warnings get around these limitations by allowing finer control
626over where warnings can or can't be tripped.
627
628=head2 Controlling Warnings from the Command Line
629
630There are three Command Line flags that can be used to control when
631warnings are (or aren't) produced:
632
633=over 5
634
635=item B<-w>
636X<-w>
637
638This is the existing flag. If the lexical warnings pragma is B<not>
639used in any of you code, or any of the modules that you use, this flag
640will enable warnings everywhere. See L<Backward Compatibility> for
641details of how this flag interacts with lexical warnings.
642
643=item B<-W>
644X<-W>
645
3c3f8cd6 646If the B<-W> flag is used on the command line, it will enable all warnings
a7f2b7af
RS
647throughout the program regardless of whether warnings were disabled
648locally using C<no warnings> or C<$^W =0>.
649This includes all files that get
650included via C<use>, C<require> or C<do>.
651Think of it as the Perl equivalent of the "lint" command.
652
653=item B<-X>
654X<-X>
655
3c3f8cd6 656Does the exact opposite to the B<-W> flag, i.e. it disables all warnings.
ea5519d6
AB
657
658=back
659
a7f2b7af
RS
660=head2 Backward Compatibility
661
662If you are used to working with a version of Perl prior to the
663introduction of lexically scoped warnings, or have code that uses both
664lexical warnings and C<$^W>, this section will describe how they interact.
665
666How Lexical Warnings interact with B<-w>/C<$^W>:
667
668=over 5
669
670=item 1.
671
672If none of the three command line flags (B<-w>, B<-W> or B<-X>) that
673control warnings is used and neither C<$^W> nor the C<warnings> pragma
674are used, then default warnings will be enabled and optional warnings
675disabled.
676This means that legacy code that doesn't attempt to control the warnings
677will work unchanged.
678
679=item 2.
680
681The B<-w> flag just sets the global C<$^W> variable as in 5.005. This
682means that any legacy code that currently relies on manipulating C<$^W>
56873d42 683to control warning behavior will still work as is.
a7f2b7af
RS
684
685=item 3.
686
687Apart from now being a boolean, the C<$^W> variable operates in exactly
688the same horrible uncontrolled global way, except that it cannot
689disable/enable default warnings.
690
691=item 4.
692
693If a piece of code is under the control of the C<warnings> pragma,
694both the C<$^W> variable and the B<-w> flag will be ignored for the
695scope of the lexical warning.
696
697=item 5.
698
699The only way to override a lexical warnings setting is with the B<-W>
700or B<-X> command line flags.
701
702=back
703
704The combined effect of 3 & 4 is that it will allow code which uses
705the C<warnings> pragma to control the warning behavior of $^W-type
706code (using a C<local $^W=0>) if it really wants to, but not vice-versa.
707
708=head2 Category Hierarchy
709X<warning, categories>
710
711A hierarchy of "categories" have been defined to allow groups of warnings
712to be enabled/disabled in isolation.
713
714The current hierarchy is:
715
3c3f8cd6
AB
716 all -+
717 |
718 +- closure
719 |
720 +- deprecated
721 |
722 +- exiting
723 |
724 +- experimental --+
725 | |
726 | +- experimental::autoderef
727 | |
728 | +- experimental::const_attr
729 | |
730 | +- experimental::lexical_subs
731 | |
732 | +- experimental::lexical_topic
733 | |
734 | +- experimental::postderef
735 | |
736 | +- experimental::re_strict
737 | |
738 | +- experimental::refaliasing
739 | |
740 | +- experimental::regex_sets
741 | |
742 | +- experimental::signatures
743 | |
744 | +- experimental::smartmatch
745 | |
746 | +- experimental::win32_perlio
747 |
748 +- glob
749 |
750 +- imprecision
751 |
752 +- io ------------+
753 | |
754 | +- closed
755 | |
756 | +- exec
757 | |
758 | +- layer
759 | |
760 | +- newline
761 | |
762 | +- pipe
763 | |
764 | +- syscalls
765 | |
766 | +- unopened
767 |
768 +- locale
769 |
770 +- misc
771 |
772 +- missing
773 |
774 +- numeric
775 |
776 +- once
777 |
778 +- overflow
779 |
780 +- pack
781 |
782 +- portable
783 |
784 +- recursion
785 |
786 +- redefine
787 |
788 +- redundant
789 |
790 +- regexp
791 |
792 +- severe --------+
793 | |
794 | +- debugging
795 | |
796 | +- inplace
797 | |
798 | +- internal
799 | |
800 | +- malloc
801 |
802 +- signal
803 |
804 +- substr
805 |
806 +- syntax --------+
807 | |
808 | +- ambiguous
809 | |
810 | +- bareword
811 | |
812 | +- digit
813 | |
814 | +- illegalproto
815 | |
816 | +- parenthesis
817 | |
818 | +- precedence
819 | |
820 | +- printf
821 | |
822 | +- prototype
823 | |
824 | +- qw
825 | |
826 | +- reserved
827 | |
828 | +- semicolon
829 |
830 +- taint
831 |
832 +- threads
833 |
834 +- uninitialized
835 |
836 +- unpack
837 |
838 +- untie
839 |
840 +- utf8 ----------+
841 | |
842 | +- non_unicode
843 | |
844 | +- nonchar
845 | |
846 | +- surrogate
847 |
848 +- void
a7f2b7af
RS
849
850Just like the "strict" pragma any of these categories can be combined
851
852 use warnings qw(void redefine);
853 no warnings qw(io syntax untie);
854
855Also like the "strict" pragma, if there is more than one instance of the
56873d42 856C<warnings> pragma in a given scope the cumulative effect is additive.
a7f2b7af
RS
857
858 use warnings qw(void); # only "void" warnings enabled
859 ...
860 use warnings qw(io); # only "void" & "io" warnings enabled
861 ...
862 no warnings qw(void); # only "io" warnings enabled
863
864To determine which category a specific warning has been assigned to see
865L<perldiag>.
866
867Note: Before Perl 5.8.0, the lexical warnings category "deprecated" was a
868sub-category of the "syntax" category. It is now a top-level category
869in its own right.
870
3664866e
AB
871Note: Before 5.21.0, the "missing" lexical warnings category was
872internally defined to be the same as the "uninitialized" category. It
873is now a top-level category in its own right.
874
a7f2b7af
RS
875=head2 Fatal Warnings
876X<warning, fatal>
877
878The presence of the word "FATAL" in the category list will escalate any
879warnings detected from the categories specified in the lexical scope
880into fatal errors. In the code below, the use of C<time>, C<length>
881and C<join> can all produce a C<"Useless use of xxx in void context">
882warning.
883
884 use warnings;
885
886 time;
887
888 {
889 use warnings FATAL => qw(void);
890 length "abc";
891 }
892
893 join "", 1,2,3;
894
895 print "done\n";
896
897When run it produces this output
898
899 Useless use of time in void context at fatal line 3.
56873d42 900 Useless use of length in void context at fatal line 7.
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RS
901
902The scope where C<length> is used has escalated the C<void> warnings
903category into a fatal error, so the program terminates immediately when it
904encounters the warning.
905
906To explicitly turn off a "FATAL" warning you just disable the warning
907it is associated with. So, for example, to disable the "void" warning
908in the example above, either of these will do the trick:
909
910 no warnings qw(void);
911 no warnings FATAL => qw(void);
912
913If you want to downgrade a warning that has been escalated into a fatal
914error back to a normal warning, you can use the "NONFATAL" keyword. For
915example, the code below will promote all warnings into fatal errors,
916except for those in the "syntax" category.
917
918 use warnings FATAL => 'all', NONFATAL => 'syntax';
919
920As of Perl 5.20, instead of C<< use warnings FATAL => 'all'; >> you can
921use:
922
923 use v5.20; # Perl 5.20 or greater is required for the following
924 use warnings 'FATAL'; # short form of "use warnings FATAL => 'all';"
925
926If you want your program to be compatible with versions of Perl before
9275.20, you must use C<< use warnings FATAL => 'all'; >> instead. (In
928previous versions of Perl, the behavior of the statements
929C<< use warnings 'FATAL'; >>, C<< use warnings 'NONFATAL'; >> and
930C<< no warnings 'FATAL'; >> was unspecified; they did not behave as if
931they included the C<< => 'all' >> portion. As of 5.20, they do.)
932
933B<NOTE:> Users of FATAL warnings, especially
934those using C<< FATAL => 'all' >>
935should be fully aware that they are risking future portability of their
936programs by doing so. Perl makes absolutely no commitments to not
937introduce new warnings, or warnings categories in the future, and indeed
938we explicitly reserve the right to do so. Code that may not warn now may
939warn in a future release of Perl if the Perl5 development team deems it
940in the best interests of the community to do so. Should code using FATAL
941warnings break due to the introduction of a new warning we will NOT
942consider it an incompatible change. Users of FATAL warnings should take
943special caution during upgrades to check to see if their code triggers
944any new warnings and should pay particular attention to the fine print of
945the documentation of the features they use to ensure they do not exploit
946features that are documented as risky, deprecated, or unspecified, or where
947the documentation says "so don't do that", or anything with the same sense
948and spirit. Use of such features in combination with FATAL warnings is
949ENTIRELY AT THE USER'S RISK.
950
951=head2 Reporting Warnings from a Module
952X<warning, reporting> X<warning, registering>
953
954The C<warnings> pragma provides a number of functions that are useful for
955module authors. These are used when you want to report a module-specific
956warning to a calling module has enabled warnings via the C<warnings>
957pragma.
958
959Consider the module C<MyMod::Abc> below.
960
961 package MyMod::Abc;
962
963 use warnings::register;
964
965 sub open {
966 my $path = shift;
967 if ($path !~ m#^/#) {
968 warnings::warn("changing relative path to /var/abc")
969 if warnings::enabled();
970 $path = "/var/abc/$path";
971 }
972 }
973
974 1;
975
976The call to C<warnings::register> will create a new warnings category
977called "MyMod::Abc", i.e. the new category name matches the current
978package name. The C<open> function in the module will display a warning
979message if it gets given a relative path as a parameter. This warnings
980will only be displayed if the code that uses C<MyMod::Abc> has actually
981enabled them with the C<warnings> pragma like below.
982
983 use MyMod::Abc;
984 use warnings 'MyMod::Abc';
985 ...
986 abc::open("../fred.txt");
987
988It is also possible to test whether the pre-defined warnings categories are
989set in the calling module with the C<warnings::enabled> function. Consider
990this snippet of code:
991
992 package MyMod::Abc;
993
994 sub open {
56873d42 995 warnings::warnif("deprecated",
a7f2b7af
RS
996 "open is deprecated, use new instead");
997 new(@_);
998 }
999
1000 sub new
1001 ...
1002 1;
1003
1004The function C<open> has been deprecated, so code has been included to
1005display a warning message whenever the calling module has (at least) the
1006"deprecated" warnings category enabled. Something like this, say.
1007
1008 use warnings 'deprecated';
1009 use MyMod::Abc;
1010 ...
1011 MyMod::Abc::open($filename);
1012
1013Either the C<warnings::warn> or C<warnings::warnif> function should be
1014used to actually display the warnings message. This is because they can
1015make use of the feature that allows warnings to be escalated into fatal
1016errors. So in this case
1017
1018 use MyMod::Abc;
1019 use warnings FATAL => 'MyMod::Abc';
1020 ...
1021 MyMod::Abc::open('../fred.txt');
1022
1023the C<warnings::warnif> function will detect this and die after
1024displaying the warning message.
1025
1026The three warnings functions, C<warnings::warn>, C<warnings::warnif>
1027and C<warnings::enabled> can optionally take an object reference in place
1028of a category name. In this case the functions will use the class name
1029of the object as the warnings category.
1030
1031Consider this example:
1032
1033 package Original;
1034
1035 no warnings;
1036 use warnings::register;
1037
1038 sub new
1039 {
1040 my $class = shift;
1041 bless [], $class;
1042 }
1043
1044 sub check
effd17dc
DD
1045 {
1046 my $self = shift;
1047 my $value = shift;
e476b1b5 1048
effd17dc
DD
1049 if ($value % 2 && warnings::enabled($self))
1050 { warnings::warn($self, "Odd numbers are unsafe") }
1051 }
599cee73 1052
effd17dc
DD
1053 sub doit
1054 {
1055 my $self = shift;
1056 my $value = shift;
1057 $self->check($value);
1058 # ...
1059 }
599cee73 1060
effd17dc 1061 1;
0d658bf5 1062
effd17dc 1063 package Derived;
0d658bf5 1064
effd17dc
DD
1065 use warnings::register;
1066 use Original;
1067 our @ISA = qw( Original );
1068 sub new
1069 {
1070 my $class = shift;
1071 bless [], $class;
1072 }
b88df990 1073
b88df990 1074
effd17dc 1075 1;
8457b38f 1076
56873d42 1077The code below makes use of both modules, but it only enables warnings from
effd17dc 1078C<Derived>.
8457b38f 1079
effd17dc
DD
1080 use Original;
1081 use Derived;
1082 use warnings 'Derived';
1083 my $a = Original->new();
1084 $a->doit(1);
1085 my $b = Derived->new();
1086 $a->doit(1);
6f87cb12 1087
effd17dc 1088When this code is run only the C<Derived> object, C<$b>, will generate
56873d42 1089a warning.
6f87cb12 1090
effd17dc 1091 Odd numbers are unsafe at main.pl line 7
c8028aa6 1092
effd17dc
DD
1093Notice also that the warning is reported at the line where the object is first
1094used.
c8028aa6 1095
effd17dc
DD
1096When registering new categories of warning, you can supply more names to
1097warnings::register like this:
7ac92924 1098
effd17dc
DD
1099 package MyModule;
1100 use warnings::register qw(format precision);
7ac92924 1101
effd17dc 1102 ...
d3a7d8c7 1103
effd17dc 1104 warnings::warnif('MyModule::format', '...');
599cee73 1105
effd17dc 1106=head1 FUNCTIONS
599cee73 1107
effd17dc 1108=over 4
d3a7d8c7 1109
effd17dc 1110=item use warnings::register
599cee73 1111
effd17dc
DD
1112Creates a new warnings category with the same name as the package where
1113the call to the pragma is used.
c3186b65 1114
effd17dc 1115=item warnings::enabled()
6e9af7e4 1116
effd17dc 1117Use the warnings category with the same name as the current package.
599cee73 1118
effd17dc
DD
1119Return TRUE if that warnings category is enabled in the calling module.
1120Otherwise returns FALSE.
599cee73 1121
effd17dc 1122=item warnings::enabled($category)
4c02ac93 1123
effd17dc
DD
1124Return TRUE if the warnings category, C<$category>, is enabled in the
1125calling module.
1126Otherwise returns FALSE.
6e9af7e4 1127
effd17dc 1128=item warnings::enabled($object)
6e9af7e4 1129
effd17dc
DD
1130Use the name of the class for the object reference, C<$object>, as the
1131warnings category.
c91312d5 1132
effd17dc
DD
1133Return TRUE if that warnings category is enabled in the first scope
1134where the object is used.
1135Otherwise returns FALSE.
a7f2b7af 1136
effd17dc 1137=item warnings::fatal_enabled()
599cee73 1138
effd17dc
DD
1139Return TRUE if the warnings category with the same name as the current
1140package has been set to FATAL in the calling module.
1141Otherwise returns FALSE.
6e9af7e4 1142
effd17dc 1143=item warnings::fatal_enabled($category)
6e9af7e4 1144
effd17dc
DD
1145Return TRUE if the warnings category C<$category> has been set to FATAL in
1146the calling module.
1147Otherwise returns FALSE.
6e9af7e4 1148
effd17dc 1149=item warnings::fatal_enabled($object)
6e9af7e4 1150
effd17dc
DD
1151Use the name of the class for the object reference, C<$object>, as the
1152warnings category.
6e9af7e4 1153
effd17dc
DD
1154Return TRUE if that warnings category has been set to FATAL in the first
1155scope where the object is used.
1156Otherwise returns FALSE.
599cee73 1157
effd17dc 1158=item warnings::warn($message)
9df0f64f 1159
effd17dc 1160Print C<$message> to STDERR.
8787a747 1161
effd17dc 1162Use the warnings category with the same name as the current package.
96183d25 1163
effd17dc
DD
1164If that warnings category has been set to "FATAL" in the calling module
1165then die. Otherwise return.
96183d25 1166
effd17dc 1167=item warnings::warn($category, $message)
d3a7d8c7 1168
effd17dc 1169Print C<$message> to STDERR.
d3a7d8c7 1170
effd17dc
DD
1171If the warnings category, C<$category>, has been set to "FATAL" in the
1172calling module then die. Otherwise return.
7e6d00f8 1173
effd17dc 1174=item warnings::warn($object, $message)
7e6d00f8 1175
effd17dc 1176Print C<$message> to STDERR.
8787a747 1177
effd17dc
DD
1178Use the name of the class for the object reference, C<$object>, as the
1179warnings category.
8787a747 1180
effd17dc
DD
1181If that warnings category has been set to "FATAL" in the scope where C<$object>
1182is first used then die. Otherwise return.
96183d25 1183
96183d25 1184
effd17dc 1185=item warnings::warnif($message)
96183d25 1186
effd17dc 1187Equivalent to:
7e6d00f8 1188
effd17dc
DD
1189 if (warnings::enabled())
1190 { warnings::warn($message) }
572bfd36 1191
effd17dc 1192=item warnings::warnif($category, $message)
572bfd36 1193
effd17dc 1194Equivalent to:
572bfd36 1195
effd17dc
DD
1196 if (warnings::enabled($category))
1197 { warnings::warn($category, $message) }
572bfd36 1198
effd17dc 1199=item warnings::warnif($object, $message)
4f527b71 1200
effd17dc 1201Equivalent to:
599cee73 1202
effd17dc
DD
1203 if (warnings::enabled($object))
1204 { warnings::warn($object, $message) }
d3a7d8c7 1205
effd17dc 1206=item warnings::register_categories(@names)
e476b1b5 1207
effd17dc
DD
1208This registers warning categories for the given names and is primarily for
1209use by the warnings::register pragma.
0d658bf5 1210
effd17dc 1211=back
8787a747 1212
effd17dc
DD
1213See also L<perlmodlib/Pragmatic Modules> and L<perldiag>.
1214
1215=cut
ce716c52 1216
37442d52 1217# ex: set ro: