|
Hopefully, this page is exactly what you are looking for, but if not, you can always find further assistance on Unix/Linux Forum!
Carp(3pm) Perl Programmers Reference Guide Carp(3pm)
NAME
carp - warn of errors (from perspective of caller)
cluck - warn of errors with stack backtrace
(not exported by default)
croak - die of errors (from perspective of caller)
confess - die of errors with stack backtrace
shortmess - return the message that carp and croak produce
longmess - return the message that cluck and confess produce
SYNOPSIS
use Carp;
croak "We're outta here!";
use Carp qw(cluck);
cluck "This is how we got here!";
print FH Carp::shortmess("This will have caller's details added");
print FH Carp::longmess("This will have stack backtrace added");
DESCRIPTION
The Carp routines are useful in your own modules because they act like
die() or warn(), but with a message which is more likely to be useful
to a user of your module. In the case of cluck, confess, and longmess
that context is a summary of every call in the call-stack. For a
shorter message you can use carp, croak or shortmess which report the
error as being from where your module was called. There is no guaran-
tee that that is where the error was, but it is a good educated guess.
You can also alter the way the output and logic of "Carp" works, by
changing some global variables in the "Carp" namespace. See the section
on "GLOBAL VARIABLES" below.
Here is a more complete description of how shortmess works. What it
does is search the call-stack for a function call stack where it hasn't
been told that there shouldn't be an error. If every call is marked
safe, it then gives up and gives a full stack backtrace instead. In
other words it presumes that the first likely looking potential suspect
is guilty. Its rules for telling whether a call shouldn't generate
errors work as follows:
1. Any call from a package to itself is safe.
2. Packages claim that there won't be errors on calls to or from pack-
ages explicitly marked as safe by inclusion in @CARP_NOT, or (if
that array is empty) @ISA. The ability to override what @ISA says
is new in 5.8.
3. The trust in item 2 is transitive. If A trusts B, and B trusts C,
then A trusts C. So if you do not override @ISA with @CARP_NOT,
then this trust relationship is identical to, "inherits from".
4. Any call from an internal Perl module is safe. (Nothing keeps user
modules from marking themselves as internal to Perl, but this prac-
tice is discouraged.)
5. Any call to Carp is safe. (This rule is what keeps it from report-
ing the error where you call carp/croak/shortmess.)
Forcing a Stack Trace
As a debugging aid, you can force Carp to treat a croak as a confess
and a carp as a cluck across all modules. In other words, force a
detailed stack trace to be given. This can be very helpful when trying
to understand why, or from where, a warning or error is being gener-
ated.
This feature is enabled by 'importing' the non-existent symbol 'ver-
bose'. You would typically enable it by saying
perl -MCarp=verbose script.pl
or by including the string "MCarp=verbose" in the PERL5OPT environment
variable.
Alternately, you can set the global variable $Carp::Verbose to true.
See the "GLOBAL VARIABLES" section below.
GLOBAL VARIABLES
$Carp::CarpLevel
This variable determines how many call frames are to be skipped when
reporting where an error occurred on a call to one of "Carp"'s func-
tions. For example:
$Carp::CarpLevel = 1;
sub bar { .... or _error('Wrong input') }
sub _error { Carp::carp(@_) }
This would make Carp report the error as coming from "bar"'s caller,
rather than from "_error"'s caller, as it normally would.
Defaults to 0.
$Carp::MaxEvalLen
This variable determines how many characters of a string-eval are to be
shown in the output. Use a value of 0 to show all text.
Defaults to 0.
$Carp::MaxArgLen
This variable determines how many characters of each argument to a
function to print. Use a value of 0 to show the full length of the
argument.
Defaults to 64.
$Carp::MaxArgNums
This variable determines how many arguments to each function to show.
Use a value of 0 to show all arguments to a function call.
Defaults to 8.
$Carp::Verbose
This variable makes "Carp" use the "longmess" function at all times.
This effectively means that all calls to "carp" become "cluck" and all
calls to "croak" become "confess".
Note, this is analogous to using "use Carp 'verbose'".
Defaults to 0.
BUGS
The Carp routines don't handle exception objects currently. If called
with a first argument that is a reference, they simply call die() or
warn(), as appropriate.
perl v5.8.8 2001-09-21 Carp(3pm)
Man(1) output converted with
man2html and wrapped by fishsponge
This page was generated on Sat Sep 8 16:36:51 GMT 2007
|
Your favourite pages:
No pages logged yet.
Trying to save cookie... Top 10 most popular pages:
svn man page (6161 hits)
(FreeBSD 6.2)
sqlite3 man page (5596 hits)
(openSUSE 10.2)
adv_cap_autoneg man page (5045 hits)
(Solaris 10 11_06)
CPAN man page (4791 hits)
(Suse Linux 10.1)
ssh man page (4439 hits)
(Suse Linux 10.1)
ssh-socks5-proxy-connect man page (3525 hits)
(Solaris 10 11_06)
signal man page (3394 hits)
(Suse Linux 10.1)
netcat man page (3373 hits)
(Suse Linux 10.1)
pprosetup man page (2886 hits)
(Solaris 10 11_06)
startproc man page (2738 hits)
(Suse Linux 10.1)
|
Man Pages 
