You can use header () even if your CSV does not have a header, if only to detect BOM, eol, and SEP.

open my $fh, "<", "file.csv" or die "$!";
my $csv = Text::CSV_XS->new ({ binary => 1, auto_diag => 1 });
$csv->header ($fh, { bom => 1, set_column_names => 0 });
while (my $row = $csv->getline ($fh)) {
    # ...
    }
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