diff --git a/ext/zlib/php_zlib.def b/ext/zlib/php_zlib.def
index d482041893c..27709190970 100644
--- a/ext/zlib/php_zlib.def
+++ b/ext/zlib/php_zlib.def
@@ -34,6 +34,7 @@ EXPORTS
     gzsetparams
     gzread
     gzwrite
+    gzfwrite
     gzprintf
     gzputs
     gzgets