sam-t2/devtools/amd64/man/man3/Fatal.3

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.\" ========================================================================
.\"
.IX Title "Fatal 3"
.TH Fatal 3 "2001-09-21" "perl v5.8.8" "Perl Programmers Reference Guide"
.SH "NAME"
Fatal \- replace functions with equivalents which succeed or die
.SH "SYNOPSIS"
.IX Header "SYNOPSIS"
.Vb 1
\&    use Fatal qw(open close);
.Ve
.PP
.Vb 2
\&    sub juggle { . . . }
\&    import Fatal 'juggle';
.Ve
.SH "DESCRIPTION"
.IX Header "DESCRIPTION"
\&\f(CW\*(C`Fatal\*(C'\fR 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 \f(CW\*(C`eval{}\*(C'\fR.  See perlfunc and perlvar for details.
.PP
The do-or-die equivalents are set up simply by calling Fatal's
\&\f(CW\*(C`import\*(C'\fR routine, passing it the names of the functions to be
replaced.  You may wrap both user-defined functions and overridable
\&\s-1CORE\s0 operators (except \f(CW\*(C`exec\*(C'\fR, \f(CW\*(C`system\*(C'\fR which cannot be expressed
via prototypes) in this way.
.PP
If the symbol \f(CW\*(C`:void\*(C'\fR 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
.PP
.Vb 1
\&        use Fatal qw/:void open close/;
.Ve
.PP
.Vb 4
\&        # properly checked, so no exception raised on error
\&        if(open(FH, "< /bogotic") {
\&                warn "bogo file, dude: $!";
\&        }
.Ve
.PP
.Vb 2
\&        # not checked, so error raises an exception
\&        close FH;
.Ve
.SH "AUTHOR"
.IX Header "AUTHOR"
Lionel.Cons@cern.ch
.PP
prototype updates by Ilya Zakharevich ilya@math.ohio\-state.edu