diff --git a/panda/src/express/zStreamBuf.cxx b/panda/src/express/zStreamBuf.cxx
index 7786a7b22f..c0b4c24b84 100644
--- a/panda/src/express/zStreamBuf.cxx
+++ b/panda/src/express/zStreamBuf.cxx
@@ -44,7 +44,7 @@ ZStreamBuf() {
   char *buf = new char[4096];
   char *ebuf = buf + 4096;
   setg(buf, ebuf, ebuf);
-  setp(buf, ebuf, ebuf);
+  setp(buf, ebuf);
 
 #else
   allocate();