← Index
NYTProf Performance Profile   « block view • line view • sub view »
For ddd2.pl
  Run on Tue May 25 16:52:24 2010
Reported on Tue May 25 16:56:54 2010

File /usr/local/lib/perl5/5.8.8/Carp.pm
Statements Executed 14
Statement Execution Time 1.57ms
Subroutines — ordered by exclusive time
Calls P F Exclusive
Time		 Inclusive
Time		 Subroutine
0000s0sCarp::::carpCarp::carp
0000s0sCarp::::cluckCarp::cluck
0000s0sCarp::::confessCarp::confess
0000s0sCarp::::croakCarp::croak
0000s0sCarp::::export_failCarp::export_fail
0000s0sCarp::::longmessCarp::longmess
0000s0sCarp::::shortmessCarp::shortmess
Call graph for these subroutines as a Graphviz dot language file.
Line State
ments		 Time
on line		 Calls Time
in subs		 Code
1package Carp;
2
315µsour $VERSION = '1.04';
4
5=head1 NAME
6
7carp - warn of errors (from perspective of caller)
8
9cluck - warn of errors with stack backtrace
10 (not exported by default)
11
12croak - die of errors (from perspective of caller)
13
14confess - die of errors with stack backtrace
15
16shortmess - return the message that carp and croak produce
17
18longmess - return the message that cluck and confess produce
19
20=head1 SYNOPSIS
21
22 use Carp;
23 croak "We're outta here!";
24
25 use Carp qw(cluck);
26 cluck "This is how we got here!";
27
28 print FH Carp::shortmess("This will have caller's details added");
29 print FH Carp::longmess("This will have stack backtrace added");
30
31=head1 DESCRIPTION
32
33The Carp routines are useful in your own modules because
34they act like die() or warn(), but with a message which is more
35likely to be useful to a user of your module. In the case of
36cluck, confess, and longmess that context is a summary of every
37call in the call-stack. For a shorter message you can use carp,
38croak or shortmess which report the error as being from where
39your module was called. There is no guarantee that that is where
40the error was, but it is a good educated guess.
41
42You can also alter the way the output and logic of C<Carp> works, by
43changing some global variables in the C<Carp> namespace. See the
44section on C<GLOBAL VARIABLES> below.
45
46Here is a more complete description of how shortmess works. What
47it does is search the call-stack for a function call stack where
48it hasn't been told that there shouldn't be an error. If every
49call is marked safe, it then gives up and gives a full stack
50backtrace instead. In other words it presumes that the first likely
51looking potential suspect is guilty. Its rules for telling whether
52a call shouldn't generate errors work as follows:
53
54=over 4
55
56=item 1.
57
58Any call from a package to itself is safe.
59
60=item 2.
61
62Packages claim that there won't be errors on calls to or from
63packages explicitly marked as safe by inclusion in @CARP_NOT, or
64(if that array is empty) @ISA. The ability to override what
65@ISA says is new in 5.8.
66
67=item 3.
68
69The trust in item 2 is transitive. If A trusts B, and B
70trusts C, then A trusts C. So if you do not override @ISA
71with @CARP_NOT, then this trust relationship is identical to,
72"inherits from".
73
74=item 4.
75
76Any call from an internal Perl module is safe. (Nothing keeps
77user modules from marking themselves as internal to Perl, but
78this practice is discouraged.)
79
80=item 5.
81
82Any call to Carp is safe. (This rule is what keeps it from
83reporting the error where you call carp/croak/shortmess.)
84
85=back
86
87=head2 Forcing a Stack Trace
88
89As a debugging aid, you can force Carp to treat a croak as a confess
90and a carp as a cluck across I<all> modules. In other words, force a
91detailed stack trace to be given. This can be very helpful when trying
92to understand why, or from where, a warning or error is being generated.
93
94This feature is enabled by 'importing' the non-existent symbol
95'verbose'. You would typically enable it by saying
96
97 perl -MCarp=verbose script.pl
98
99or by including the string C<MCarp=verbose> in the PERL5OPT
100environment variable.
101
102Alternately, you can set the global variable C<$Carp::Verbose> to true.
103See the C<GLOBAL VARIABLES> section below.
104
105=cut
106
107# This package is heavily used. Be small. Be fast. Be good.
108
109# Comments added by Andy Wardley <abw@kfs.org> 09-Apr-98, based on an
110# _almost_ complete understanding of the package. Corrections and
111# comments are welcome.
112
113# The members of %Internal are packages that are internal to perl.
114# Carp will not report errors from within these packages if it
115# can. The members of %CarpInternal are internal to Perl's warning
116# system. Carp will not report errors from within these packages
117# either, and will not report calls *to* these packages for carp and
118# croak. They replace $CarpLevel, which is deprecated. The
119# $Max(EvalLen|(Arg(Len|Nums)) variables are used to specify how the eval
120# text and function arguments should be formatted when printed.
121
122# Comments added by Jos I. Boumans <kane@dwim.org> 11-Aug-2004
123# I can not get %CarpInternal or %Internal to work as advertised,
124# therefor leaving it out of the below documentation.
125# $CarpLevel may be decprecated according to the last comment, but
126# after 6 years, it's still around and in heavy use ;)
127
128=pod
129
130=head1 GLOBAL VARIABLES
131
132=head2 $Carp::CarpLevel
133
134This variable determines how many call frames are to be skipped when
135reporting where an error occurred on a call to one of C<Carp>'s
136functions. For example:
137
138 $Carp::CarpLevel = 1;
139 sub bar { .... or _error('Wrong input') }
140 sub _error { Carp::carp(@_) }
141
142This would make Carp report the error as coming from C<bar>'s caller,
143rather than from C<_error>'s caller, as it normally would.
144
145Defaults to C<0>.
146
147=head2 $Carp::MaxEvalLen
148
149This variable determines how many characters of a string-eval are to
150be shown in the output. Use a value of C<0> to show all text.
151
152Defaults to C<0>.
153
154=head2 $Carp::MaxArgLen
155
156This variable determines how many characters of each argument to a
157function to print. Use a value of C<0> to show the full length of the
158argument.
159
160Defaults to C<64>.
161
162=head2 $Carp::MaxArgNums
163
164This variable determines how many arguments to each function to show.
165Use a value of C<0> to show all arguments to a function call.
166
167Defaults to C<8>.
168
169=head2 $Carp::Verbose
170
171This variable makes C<Carp> use the C<longmess> function at all times.
172This effectively means that all calls to C<carp> become C<cluck> and
173all calls to C<croak> become C<confess>.
174
175Note, this is analogous to using C<use Carp 'verbose'>.
176
177Defaults to C<0>.
178
179=cut
180
181
18217µs$CarpInternal{Carp}++;
18315µs$CarpInternal{warnings}++;
18414µs$CarpLevel = 0; # How many extra package levels to skip on carp.
185 # How many calls to skip on confess.
186 # Reconciling these notions is hard, use
187 # %Internal and %CarpInternal instead.
18814µs$MaxEvalLen = 0; # How much eval '...text...' to show. 0 = all.
18914µs$MaxArgLen = 64; # How much of each argument to print. 0 = all.
19014µs$MaxArgNums = 8; # How many arguments to print. 0 = all.
19114µs$Verbose = 0; # If true then make shortmess call longmess instead
192
19311.48msrequire Exporter;
194113µs@ISA = ('Exporter');
19516µs@EXPORT = qw(confess croak carp);
19617µs@EXPORT_OK = qw(cluck verbose longmess shortmess);
19715µs@EXPORT_FAIL = qw(verbose); # hook to enable verbose mode
198
199=head1 BUGS
200
201The Carp routines don't handle exception objects currently.
202If called with a first argument that is a reference, they simply
203call die() or warn(), as appropriate.
204
205=cut
206
207# if the caller specifies verbose usage ("perl -MCarp=verbose script.pl")
208# then the following method will be called by the Exporter which knows
209# to do this thanks to @EXPORT_FAIL, above. $_[1] will contain the word
210# 'verbose'.
211
212sub export_fail {
213 shift;
214 $Verbose = shift if $_[0] eq 'verbose';
215 return @_;
216}
217
218
219# longmess() crawls all the way up the stack reporting on all the function
220# calls made. The error string, $error, is originally constructed from the
221# arguments passed into longmess() via confess(), cluck() or shortmess().
222# This gets appended with the stack trace messages which are generated for
223# each function call on the stack.
224
225sub longmess {
226 {
227 local($@, $!);
228 # XXX fix require to not clear $@ or $!?
229 # don't use require unless we need to (for Safe compartments)
230 require Carp::Heavy unless $INC{"Carp/Heavy.pm"};
231 }
232 # Icky backwards compatibility wrapper. :-(
233 my $call_pack = caller();
234 if ($Internal{$call_pack} or $CarpInternal{$call_pack}) {
235 return longmess_heavy(@_);
236 }
237 else {
238 local $CarpLevel = $CarpLevel + 1;
239 return longmess_heavy(@_);
240 }
241}
242
243
244# shortmess() is called by carp() and croak() to skip all the way up to
245# the top-level caller's package and report the error from there. confess()
246# and cluck() generate a full stack trace so they call longmess() to
247# generate that. In verbose mode shortmess() calls longmess() so
248# you always get a stack trace
249
250sub shortmess { # Short-circuit &longmess if called via multiple packages
251 {
252 local($@, $!);
253 # XXX fix require to not clear $@ or $!?
254 # don't use require unless we need to (for Safe compartments)
255 require Carp::Heavy unless $INC{"Carp/Heavy.pm"};
256 }
257 # Icky backwards compatibility wrapper. :-(
258 my $call_pack = caller();
259 local @CARP_NOT = caller();
260 shortmess_heavy(@_);
261}
262
263
264# the following four functions call longmess() or shortmess() depending on
265# whether they should generate a full stack trace (confess() and cluck())
266# or simply report the caller's package (croak() and carp()), respectively.
267# confess() and croak() die, carp() and cluck() warn.
268
269sub croak { die shortmess @_ }
270sub confess { die longmess @_ }
271sub carp { warn shortmess @_ }
272sub cluck { warn longmess @_ }
273
274120µs1;
Report produced by the NYTProf 3.11 Perl profiler, developed by Tim Bunce and Adam Kaplan.