How can I write a function's output to a scalar?

echosilex has asked for the wisdom of the Perl Monks concerning the following question:

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Re: How can I write a function's output to a scalar? by ackohno (Scribe) on Jul 13, 2002 at 03:13 UTC
The question is a bit vague, I assume you mean to do something like this: `#!/usr/bin/perl -w use strict; my ($num1,$num2); $num1=2; $num2=sum($num1,$num1); print "$num2\n"; # Sum: returns the sum of all arguments. sub sum { my $ret; $ret=0; for(@_){$ret+=$_} return $ret; }` [download] `return` tells perl what the subroutine should give back when called, so `$num2` is given the final value of `$ret` in the subroutine sum.	[reply] [d/l] [select]
Re: How can I write a function's output to a scalar? by runrig (Abbot) on Jul 13, 2002 at 05:43 UTC
Do you mean if the function print's to STDOUT? You could maybe use local to temporarily turn STDOUT into a tied IO::Scalar filehandle...haven't tried it myself but worth a try.	[reply]
Re: How can I write a function's output to a scalar? by Abigail-II (Bishop) on Jul 16, 2002 at 14:39 UTC
You can do it with a pipe-open, as described in `man perlipc`. `#!/usr/bin/perl use strict; use warnings 'all'; sub my_function { # Does a lot, then writes print "Foobar!"; } my $pid = open my $kid => "-\|"; die "Failed to fork: $!\n" unless defined $pid; unless ($pid) { my_function; exit; } my $result; { local $/; $result = <$kid>; close $kid or die "Failed to close pipe: $!\n"; } print "Got: $result\n";` [download] Abigail	[reply] [d/l] [select]
Re: How can I write a function's output to a scalar? by Abstraction (Friar) on Jul 16, 2002 at 14:01 UTC
As a general rule functions should always return a value not print that value out. Following this rule will avoid problems like this. But if you don't have the option of modifying the function you'll have to do some trickery with STDOUT.	[reply]