bart's comment on closures is exactly the reason for your problem. See this simplified example:
use strict;
use warnings;
sub func {
my $calls = shift;
my $strange = "Call $calls";
print "In func (start): $strange\n";
sub subfunc1 {
print "In subfunc1: $strange\n";
$strange .= " even";
}
sub subfunc2 {
print "In subfunc2: $strange\n";
}
subfunc1();
subfunc2();
print "In func (end): $strange\n";
}
func(1);
func(2);
func(3);
func(4);
which creates the following output (including a couple of warnings!):
Variable "$strange" will not stay shared at closure2.pl line 10.
Variable "$strange" will not stay shared at closure2.pl line 15.
In func (start): Call 1
In subfunc1: Call 1
In subfunc2: Call 1 even
In func (end): Call 1 even
In func (start): Call 2
In subfunc1: Call 1 even
In subfunc2: Call 1 even even
In func (end): Call 2
In func (start): Call 3
In subfunc1: Call 1 even even
In subfunc2: Call 1 even even even
In func (end): Call 3
In func (start): Call 4
In subfunc1: Call 1 even even even
In subfunc2: Call 1 even even even even
In func (end): Call 4
which clearly demonstrates that the variable $strange in the subfuncs is decoupled from $strange in func in the second and subsequent calls to func. The warnings also tell the same story.
UPDATE: Compare to the following:
use strict;
use warnings;
my $strange;
sub subfunc1 {
print "In subfunc1: $strange\n";
$strange .= " even";
}
sub subfunc2 {
print "In subfunc2: $strange\n";
}
sub func {
my $calls = shift;
$strange = "Call $calls";
print "In func (start): $strange\n";
subfunc1();
subfunc2();
print "In func (end): $strange\n";
}
func(1);
func(2);
func(3);
func(4);
whose output is probably what you expected. Whether or not this is good style is a diffent question ...