On 7/14/05, Beast <[EMAIL PROTECTED]> wrote:
>
> I coudn't find any reference (yet) the meaning of 0; or 1; in the end of
> perl program.
In the examples in "perldoc perlmod" you will find
1; # don't forget to return a true value from the file
This is needed when you do a 'require' over a Perl module (which is a
Perl package in a file). The same applies to 'use' which does a
'require' as its first step. Perl programs or packages within the same
file don't need this. Or else a program simple as 'print("Hello,
World"); undef" would not work, but it does. As Chris Devers has said
it has to do with the return value of the last statement. This is
interpreted by 'require' as meaning everything was fine during the
initialization of the Perl module. Most of the time, we finish the
module just with "1;", but more deeper things could be done. An
example is a Perl module attached to a configuration file: it that
configuration could not be read, it is better to die than to continue.
(This is not the perfect example: something sensible could be done
with defaults rather than blowing in user's face).
For references, take a look at "perldoc -f require".
> It means exit or return value? when I explicitly type "return 0;" it
> gives error,
You return only from a sub.
> but when I give "exit 100;" the value of $$ isn't 100 anyway.
'exit' finishes the program immediately. $? (if in shell) catches the exit code:
$ perl -e "exit(100)"
$ echo $?
100
Regards,
Adriano.
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