man > Fatal

Fatal(3perl)                      Perl Programmers Reference Guide                      Fatal(3perl)

NAME
       Fatal - Replace functions with equivalents which succeed or die

SYNOPSIS
           use Fatal qw(open close);

           open(my $fh, "<", $filename);  # No need to check errors!

           use File::Copy qw(move);
           use Fatal qw(move);

           move($file1, $file2); # No need to check errors!

           sub juggle { . . . }
           Fatal->import('juggle');

BEST PRACTICE
       Fatal has been obsoleted by the new autodie pragma. Please use autodie in preference to
       "Fatal".  autodie supports lexical scoping, throws real exception objects, and provides much
       nicer error messages.

       The use of ":void" with Fatal is discouraged.

DESCRIPTION
       "Fatal" provides a way to conveniently replace functions which normally return a false value
       when they fail with equivalents which raise exceptions if they are not successful.  This lets
       you use these functions without having to test their return values explicitly on each call.
       Exceptions can be caught using "eval{}".  See perlfunc and perlvar for details.

       The do-or-die equivalents are set up simply by calling Fatal's "import" routine, passing it
       the names of the functions to be replaced.  You may wrap both user-defined functions and
       overridable CORE operators (except "exec", "system", "print", or any other built-in that
       cannot be expressed via prototypes) in this way.

       If the symbol ":void" appears in the import list, then functions named later in that import
       list raise an exception only when these are called in void context--that is, when their
       return values are ignored.  For example

           use Fatal qw/:void open close/;

           # properly checked, so no exception raised on error
           if (not open(my $fh, '<', '/bogotic') {
               warn "Can't open /bogotic: $!";
           }

           # not checked, so error raises an exception
           close FH;

       The use of ":void" is discouraged, as it can result in exceptions not being thrown if you
       accidentally call a method without void context.  Use autodie instead if you need to be able
       to disable autodying/Fatal behaviour for a small block of code.

DIAGNOSTICS
       Bad subroutine name for Fatal: %s
           You've  called  "Fatal"  with an argument that doesn't look like a subroutine name, nor a
           switch that this version of Fatal understands.

       %s is not a Perl subroutine
           You've asked "Fatal" to try and replace a subroutine which does not exist, or has not yet
           been defined.

       %s is neither a builtin, nor a Perl subroutine
           You've asked "Fatal" to replace a subroutine, but it's not a Perl built-in,  and  "Fatal"
           couldn't  find  it  as a regular subroutine.  It either doesn't exist or has not yet been
           defined.

       Cannot make the non-overridable %s fatal
           You've tried to use "Fatal" on a Perl built-in that can't be overridden, such as  "print"
           or  "system", which means that "Fatal" can't help you, although some other modules might.
           See the "SEE ALSO" section of this documentation.

       Internal error: %s
           You've found a bug in "Fatal".  Please report it using the "perlbug" command.

BUGS
       "Fatal" clobbers the context in which a function is called  and  always  makes  it  a  scalar
       context, except when the ":void" tag is used.  This problem does not exist in autodie.

       "Used  only  once"  warnings  can be generated when "autodie" or "Fatal" is used with package
       filehandles (eg, "FILE").  It's strongly recommended you use scalar filehandles instead.

AUTHOR
       Original module by Lionel Cons (CERN).

       Prototype updates by Ilya Zakharevich <ilya AT math.edu>.

       autodie support, bugfixes, extended diagnostics, "system" support, and major  overhauling  by
       Paul Fenwick <pjf AT perltraining.au>

LICENSE
       This module is free software, you may distribute it under the same terms as Perl itself.

SEE ALSO
       autodie for a nicer way to use lexical Fatal.

       IPC::System::Simple for a similar idea for calls to system() and backticks.

perl v5.38.2                                 2026-08-18                                 Fatal(3perl)