use Text::CSV_XS;

my $csv = Text::CSV_XS->new();

open(my $IN, '<', 'test.csv'); # ok
open(IN, '<', 'test.csv');     # nope

my $row = $csv->getline(<DATA>); # nope - Usage: Text::CSV_XS::getline(self, io) at test_02.pl line 11, <IN> line 2.
my $row = $csv->getline(<IN>);   # nope - Usage: Text::CSV_XS::getline(self, io) at test_02.pl line 11, <IN> line 2.
my $row = $csv->getline($IN);    # ok

print ${$row}[0];

__DATA__
a,b,c
d,e,f