Thanks for the suggestion, though I solved my actual problem per the response below (localizing $. wherever my module performed a seek() or used <>).
Instead of using IO::File as you propose, since open()'ed files are automatically IO::Handles, you can just "use IO::Handle;" to provide the input_line_number method (note the continue):
use strict;
use warnings;
use IO::Handle;
while (<>) {
my $lineno = ARGV->input_line_number;
# print a status message every 100 lines
warn "Processing $ARGV line $lineno\n" unless $lineno % 100;
# do some processing stuff
} continue {
close ARGV if ARGV->eof; # else input_line_number won't reset per-
+file
}
(Update:) s/eof/ARGV->eof/ in the code example. (else a poorly written function, like my original seeky() would let the eof refer to the wrong file)