近日分析extmail的源代码，看到Carp的perl模块，有些搞不懂，perldoc一把，了解了其用法，放在这里备忘！

Carp模块提供了carp(),croak(),confess(),cluck(),shortmess(),longmess()六个函数，这些函数产生的错误信息与warn()，die()类似。不同之处在于，后者标识的是出现错误的行号，前者产生调用错误的子程序命令行位置。

# script_1 source code: warn and die function

#!/usr/bin/perl
package MyPackage ;
sub my_fun {
        print "This is warn and die function output message!/n" ;
        warn("warn") ;
        die("die") ;
}

程序输出：

This is warn and die function output message!
warn at carp.pl line 8.
die at carp.pl line 9.

script 2:source code --carp croak

#!/usr/bin/perl
package MyPackage ;
use Carp ;
sub my_carp{
        print "This is Carp Module function carp croak and confess output message!/n" ;
        carp("carp") ;
        croak("croak") ;
        confess("confess") ;
}
package main ;
 MyPackage::my_carp() ;

程序输出：

[root@mail bash]# perl carp.pl
This is Carp Module function carp croak and confess output message!
carp at carp.pl line 20
croak at carp.pl line 20

script 3 source code -- confess

#!/usr/bin/perl
use Carp ;
 
sub one {
        two() ;
}
sub two {
        three() ;
}
sub three {
        confess("confess") ;
}
one() ;

程序输出：

[root@mail bash]# perl carp_confess.pl
confess at carp_confess.pl line 12
        main::three() called at carp_confess.pl line 9
        main::two() called at carp_confess.pl line 6
        main::one() called at carp_confess.pl line 14

script 4 source code :-- cluck shortmess and longmess

use Carp qw(cluck) ;
cluck "This is how we got here!" ;
print STDOUT Carp::shortmess("This will have caller's details added") ;
print STDOUT Carp::longmess("This will have stack backtrace added") ;

程序输出：

This is how we got here! at new_carp.pl line 3
This will have caller's details added at new_carp.pl line 5
This will have stack backtrace added at new_carp.pl line 6

大概就这么大了。就跟使用warn和die一样的。这个模块能产生更多的错误信息。