From: Dave Mitchell Date: Tue, 28 Jun 2005 11:28:20 +0000 (+0000) Subject: move Carp.pod back into Carp.pm X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=commitdiff_plain;h=0cda2667486fc2b14e2c3c31787368885ae92aa2;p=p5sagit%2Fp5-mst-13.2.git move Carp.pod back into Carp.pm p4raw-id: //depot/perl@25006 --- diff --git a/MANIFEST b/MANIFEST index 1ca6bbc..747a1eb 100644 --- a/MANIFEST +++ b/MANIFEST @@ -1252,7 +1252,6 @@ lib/bytes.t bytes.pm test lib/cacheout.pl Manages output filehandles when you need too many lib/Carp/Heavy.pm Error message workhorse lib/Carp.pm Error message base class -lib/Carp.pod Documentation for Carp lib/Carp.t See if Carp works lib/CGI/Apache.pm Support for Apache's Perl module lib/CGI/Carp.pm Log server errors with helpful context diff --git a/lib/Carp.pm b/lib/Carp.pm index ea7cd05..4f161b5 100644 --- a/lib/Carp.pm +++ b/lib/Carp.pm @@ -37,3 +37,161 @@ sub carp { warn shortmess @_ } sub cluck { warn longmess @_ } 1; +__END__ + +=head1 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 + +=head1 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"); + +=head1 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 guarantee 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 C works, by +changing some global variables in the C namespace. See the +section on C 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: + +=over 4 + +=item 1. + +Any call from a package to itself is safe. + +=item 2. + +Packages claim that there won't be errors on calls to or from +packages 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. + +=item 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". + +=item 4. + +Any call from an internal Perl module is safe. (Nothing keeps +user modules from marking themselves as internal to Perl, but +this practice is discouraged.) + +=item 5. + +Any call to Carp is safe. (This rule is what keeps it from +reporting the error where you call carp/croak/shortmess.) + +=back + +=head2 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 I 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 generated. + +This feature is enabled by 'importing' the non-existent symbol +'verbose'. You would typically enable it by saying + + perl -MCarp=verbose script.pl + +or by including the string C in the PERL5OPT +environment variable. + +Alternately, you can set the global variable C<$Carp::Verbose> to true. +See the C section below. + +=head1 GLOBAL VARIABLES + +=head2 $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 C's +functions. 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 C's caller, +rather than from C<_error>'s caller, as it normally would. + +Defaults to C<0>. + +=head2 $Carp::MaxEvalLen + +This variable determines how many characters of a string-eval are to +be shown in the output. Use a value of C<0> to show all text. + +Defaults to C<0>. + +=head2 $Carp::MaxArgLen + +This variable determines how many characters of each argument to a +function to print. Use a value of C<0> to show the full length of the +argument. + +Defaults to C<64>. + +=head2 $Carp::MaxArgNums + +This variable determines how many arguments to each function to show. +Use a value of C<0> to show all arguments to a function call. + +Defaults to C<8>. + +=head2 $Carp::Verbose + +This variable makes C use the C function at all times. +This effectively means that all calls to C become C and +all calls to C become C. + +Note, this is analogous to using C. + +Defaults to C<0>. + + +=head1 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. + diff --git a/lib/Carp.pod b/lib/Carp.pod deleted file mode 100644 index f77420d..0000000 --- a/lib/Carp.pod +++ /dev/null @@ -1,156 +0,0 @@ -=head1 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 - -=head1 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"); - -=head1 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 guarantee 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 C works, by -changing some global variables in the C namespace. See the -section on C 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: - -=over 4 - -=item 1. - -Any call from a package to itself is safe. - -=item 2. - -Packages claim that there won't be errors on calls to or from -packages 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. - -=item 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". - -=item 4. - -Any call from an internal Perl module is safe. (Nothing keeps -user modules from marking themselves as internal to Perl, but -this practice is discouraged.) - -=item 5. - -Any call to Carp is safe. (This rule is what keeps it from -reporting the error where you call carp/croak/shortmess.) - -=back - -=head2 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 I 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 generated. - -This feature is enabled by 'importing' the non-existent symbol -'verbose'. You would typically enable it by saying - - perl -MCarp=verbose script.pl - -or by including the string C in the PERL5OPT -environment variable. - -Alternately, you can set the global variable C<$Carp::Verbose> to true. -See the C section below. - -=head1 GLOBAL VARIABLES - -=head2 $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 C's -functions. 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 C's caller, -rather than from C<_error>'s caller, as it normally would. - -Defaults to C<0>. - -=head2 $Carp::MaxEvalLen - -This variable determines how many characters of a string-eval are to -be shown in the output. Use a value of C<0> to show all text. - -Defaults to C<0>. - -=head2 $Carp::MaxArgLen - -This variable determines how many characters of each argument to a -function to print. Use a value of C<0> to show the full length of the -argument. - -Defaults to C<64>. - -=head2 $Carp::MaxArgNums - -This variable determines how many arguments to each function to show. -Use a value of C<0> to show all arguments to a function call. - -Defaults to C<8>. - -=head2 $Carp::Verbose - -This variable makes C use the C function at all times. -This effectively means that all calls to C become C and -all calls to C become C. - -Note, this is analogous to using C. - -Defaults to C<0>. - - -=head1 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. -