Upgraded to 8.1 a custom plugin resCount error

[jfld]

I upgraded a site to 8.1 and only one custom plugin has an error with

    array_push($resultsArr, $tempArr);

    $resCount++; (this line shows the error)

Is there another way to write this line to resolve the issue? I've tried Googling for this issue, not seeing anything to resolve this.

The plugin (search with KOHA and Wordpress) appears to be working but this shows error in the log.

[requinix]

What error? Undefined variable?

[jfld]

I got this sorted out now changing $resCount 0;