I'd ask Excel, through Win32::OLE. Most likely, iterating over Application.Workbooks or somesuch should yield all filenames of all open files.

Thanks for that. I looked in the link and found enum for all objects and thought that may give what I wanted.
Therefore I wrote some Perl (below) to test it.
Unfortunately, the count was always zero no matter how many Excel files were open.
Googling for Excel and Enum, I did find a site where someone was trying gain access to a file by requesting a handle to it.
I thought that this may give what I wanted on the basis that it would only return a handle if the file was there but not opened.
I can easily test if a file is there – if it is not it cannot be open.
This is also in the Perl code below. Unfortunately this did not work either since it always returned a handle and if the file was not open, it opened Excel with a ‘blank’ screen.
Can anyone give me a clue as to what to do next?


use OLE;
use Win32::OLE::Const "Microsoft Excel";
use strict "vars";
my ($Count, $file, $ML);
$Count = Win32::OLE->EnumAllObjects(sub {
            my $Object = shift;
            my $Class = Win32::OLE->QueryObjectType($Object);
            printf "# Object=%s Class=%s\n", $Object, $Class;
        });
print "count <$Count>\n";
$file  = "C:\\abcd.xlsx";
$ML = Win32::OLE->GetObject($file)
or print "can't get a handle on '$file'";
print "$ML\n";
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Again, why don't you ask Excel about its open files?

# From memory, as I don't have Excel at hand currently
use Win32::OLE 'in';
my $excel = Win32::OLE->CreateObject('Excel.Application');

for my $wb (in($excel->{Workbooks})) {
    print $wb->{Filename},"\n";
};
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