From b83e90849fe2bb9f0e4a515c2efa7519d675079e Mon Sep 17 00:00:00 2001
From: rudolfkoenig <>
Date: Sat, 27 Jun 2020 09:52:31 +0000
Subject: [PATCH] fhem.pl: fix rare addToWriteBuffer bug

git-svn-id: https://svn.fhem.de/fhem/trunk@22281 2b470e98-0d58-463d-a4d8-8e2adae1ed80
---
 fhem/fhem.pl | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fhem/fhem.pl b/fhem/fhem.pl
index bb531a79c..3a20a27ff 100755
--- a/fhem/fhem.pl
+++ b/fhem/fhem.pl
@@ -5342,7 +5342,7 @@ addToWritebuffer($$@)
   }
 
   $hash->{WBCallback} = $callback;
-  if(!$hash->{$wbName}) {
+  if(!defined($hash->{$wbName})) {
     $hash->{$wbName} = $txt;
   } elsif($nolimit || length($hash->{$wbName}) < 1024000) {
     $hash->{$wbName} .= $txt;