in reply to using exit and number 1 at end of file

In Perl you don't need to explicitly exit as it will clean up everything for you. The "scripts" you see end with 1; are probably modules. All modules, so that use/require-ing them works, should return a true value. The easiest way to ensure this is by putting a true value at the very end of the file. 42;, for example, would also have the same effect.

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Re: Re: using exit and number 1 at end of file
by tos (Deacon) on Jun 08, 2003 at 15:48 UTC
    ... because all values unequal 0 are TRUE in perl ...
[reply]

      If you neglect overloading, all values other than "0", "", (), or undef are true. Equality to zero has nothing to do with it. Consider these: 

      my @zeroes = qw( zero 0ButTrue 00 ); 

for my $z (@zeroes) {
    print "'$z' ", $z == 0 ? 'is ' : 'is not ', "equal to zero.\n";
    print "'$z' ", $z ? 'is ' : 'is not ', "true.\n\n";
}

      [download]
      With overloading, it is even possible to get an object which is both not equal to zero and false. 
      package C; 
use overload 'bool' => sub { 0 };
use overload '=='   => sub { 0 }; 
sub new { bless {} }

package main; 
my $c = C->new;

print "\$c is not equal to zero.\n" unless $c == 0; 
print "\$c is not true.\n"          unless $c;

      [download]

      -sauoq
"My two cents aren't worth a dime.";
[reply]
[d/l]
[select]
      Non-zero return values are useful when you're using perl in a shell script, where a zero exitcode means 'true' and non-zero exitcodes generally signal various kinds of error condition.

      For example, in Bash you might want to do:

        if findfile.pl; then (something) fi

      and make findfile.pl return >0 if it doesn't find a file.

      Zarni-oh-no-this-is-PERLmonks-isn't-it-woop
[reply]
[d/l]
      ...except for undef.
[reply]
[d/l]
[reply]

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