I was using TieRegistry.pm and I kept getting an error from within the subroutine SubKeyNames. It related to returning a null hash (iirc). the hash was to have been generated and returned by _enumSubKeys. In single stepping through that code, I found that it was returning prematurely from the routine due to:

    if(  ! _NoMoreItems()  ) {
    return ();
    }
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Looking at that code, it appeared there was an assumption that an error would be generated by the call to RegEnumKeyEx (specifically, that it would be ERROR_NO_MORE_ITEMS) when there were no more subkeys. In single stepping this code, I saw that there was no error...the call to Errnum was returning zero. Modifying the code to NoMoreItems to check for either $_NoMoreItems or zero

sub _NoMoreItems
{
    my $rval;

    return $_NoMoreItems =~ /^\d/
        ?  (_ErrNum() == $_NoMoreItems || _ErrNum() == 0)
        :  _ErrMsg() =~ /$_NoMoreItems/io;
}
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eliminated the error and allowed the code to return data as expected. if this is expected, the change would have to be augmented to deal with a "no error" message as well. Has anyone know if there was an interface change for RegEnumKeyEx that resulted in it returning no error after processing the last subkey? gratz.