use strict;
my $R;
my $i=1;
sub mySub {
printf "\n\n%d. R = \"%s\"\n",$i++,$R;
unless ($R) {
print "CONDITION WORKS\n";
$R = 'some string';
}
}
print mySub(); #prints CONDITION WORKS\nsome string
print mySub(); #prints some string
print mySub(); #again
This ends up producing this for an output:
1. R = ""
CONDITION WORKS
some string
2. R = "some string"
some string
3. R = "some string"
some string
On the first iteration $R is undefined and there for in a "false" state. Therefore your print inside the "unless" gets executed and an assignment gets performed on $R. Where it gets trickier is the next iterations. Since you have unless($R) as the last evalutation the value of $R becomes the return value for the sub since you didn't specify one. see sub and search for "return" if you want more on this.
Peter L. Berghold -- Unix Professional
Peter -at- Berghold -dot- Net; AOL IM redcowdawg Yahoo IM: blue_cowdawg
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