Unspecified error (was Re: Z3950 returning two records?)

I am using the same script to go though a text file that contains issn. 
After returning the subject for 20 entires (out of 500), the script
stop with the error mesage:
"Unspecified error at test.pl line 29"
line 29 is : my $rec = $rs->record(1)
The original code was:
for (my $i = 1; $i <= $n; $i++) {
 my $rec = $rs->record($i)
       or die $rs->errmsg();
my $m = MARC::Record->new_from_usmarc($rec->rawdata());
print $m->subfield('650',"a"), "\n";

To get only one entry I got rid of the for loop:
 
      my $rec = $rs->record(1)
         or die $rs->errmsg();
    my $m = MARC::Record->new_from_usmarc($rec->rawdata());
    print "$issn\t";
    print $m->subfield('650',"a"), "\n";

Any idea? Thanks.

--sharif


Sharif Islam wrote:

> I have this simple scripts that looks up ISSN and returns the subject. 
> Why it is returning two records for the same ISSN?
> use strict;  use Net::Z3950;
> use MARC::Record;
> use MARC::File::USMARC;
> use MARC::Field;
>
>
> my $conn = new Net::Z3950::Connection('z3950.loc.gov', 
> 7090,databaseName => 'Voyager');
> my $issn="0896-9205";
> my $query = '@attr 1=8 ' . $issn;
> $conn->option(preferredRecordSyntax => "USMARC", elementSetName => 'b');
> my $rs = $conn->search($query)
>        or die $conn->errmsg();
> my $n = $rs->size();
> print "found $n records\n";
> for (my $i = 1; $i <= $n; $i++) {
>  my $rec = $rs->record($i)
>        or die $rs->errmsg();
> my $m = MARC::Record->new_from_usmarc($rec->rawdata());
> print $m->subfield('650',"a"), "\n";
> #print $rec->render();
> }
>
> # perl test.pl
> found 2 records
> Sociology
> Sociology
>


-- 
Sharif Islam                 Research Programmer
Library Systems Office       University of Illinois Urbana-Champaign
http://www.library.uiuc.edu  phone:  (217) 244-4688