Pass by reference within File Find function in perl - perl

Question

I have read a few post similar to this, but they dont quite have the answer I want. Basically, I am struggling to do pass by reference with this File::find function. The original code is huge. So I take out pieces of the code.
Note that
$node,$ref_p, $ref_alphaSUM ,$ref_rank, $ref_sorted_alpha, $output_file
are all variables or references of global variables. I need to recursively traverse through the directories and apply the &eachFile subroutine to each file, which will update my variables stated above. The "&whichFiles" subroutine just sorts the filenames.
First problem: Since not all files in the directories contains the string nfcapd, i have added the line if(/^nfcapd./) to check the if the name of the file contains this string. But since I am also passing those variables above to eachFile, the "$_" cannot be used now.
Thus, I believe This is why I kept getting the following error:(please correct me if I am wrong):
Use of uninitialized value $File::Find::name in pattern match (m//) at
./pvalues.pl line 178, <PRE> line 65184 (#1)
Line 178 is the line where if(/^nfcapd./) appears in the code below.
This leads to 2nd problem: How to do pass by reference within find function and at the same time preserving a variable for the name of file such that I can still check if the "&eachFile" is being applied to the correct files?
#!/usr/bin/perl
use strict;
use warnings;
use File::Find;
find ({wanted => \&eachFile($node,$ref_p, $ref_alphaSUM ,$ref_rank, $ref_sorted_alpha, $output_file), preprocess => \&whichFiles},$flow_data_path);
sub eachFile {
my ($node , $ref_p, $ref_alphaSUM ,$ref_rank, $ref_sorted_alpha , $output_file) = #_;
if(/^nfcapd\./){
#do something
}
}

Answer 1

To pass variables to your wanted sub, you need a closure:
sub eachFile {
my ($node , $ref_p, $ref_alphaSUM ,$ref_rank, $ref_sorted_alpha , $output_file) = #_;
if(/^nfcapd\./){
#do something
}
}
my $wanted = sub { eachFile($node,$ref_p, $ref_alphaSUM ,$ref_rank, $ref_sorted_alpha, $output_file) };
find({wanted => $wanted, ...});