carp msg

Warns of an error; reports the error as having occurred in the calling routine, not in the routine that contains the carp.

Use Carp;
carp "text of error message";

cluck msg

Warns of errors and prints a stack backtrace; reports the error as having occurred in the calling routine. Not exported by default.

use Carp qw(cluck);
cluck "text of error message";

confess msg

Dies and prints a stack backtrace. Reports the error as having occurred at the point where confess was called.

croak msg

Dies and reports error as having occurred in the calling routine.