Jonathan,

While <node>tye</node> makes some valid points, I don't think that's what the problem is here. I believe deep down in the DBD::Sybase (that's what driver you're using correct?) there is some little magic that is marking the return'ed ref as read only (disclaimer - I'm not an internals expert).

If we try some of the other fetch methods, we see some interesting things:

my $data;
do {
   while ($data = $res->fetchrow_arrayref()) {
      if ($res->{syb_result_type} == CS_ROW_RESULT) {
         if (defined $data) {
            @$data = map { defined($_) ? $_ : "" } @$data;
         }
      }
   }
}
[download]

same problem. However:

my @data;
do {
   while (@data = $res->fetchrow_array()) {
      if ($res->{syb_result_type} == CS_ROW_RESULT) {
         if (@data) {
            @data = map { defined($_) ? $_ : "" } @data;
         }
      }
   }
}
[download]

works. The funny thing is by stepping through the map statement in the debugger, the assignments to $_ are fine, it's just the final assigment to @$data that is barfing. Any Inline or XS writers out there care to comment?

-derby