diff --git a/src/FontLib/BinaryStream.php b/src/FontLib/BinaryStream.php
index 4bfbee0..39749f3 100644
--- a/src/FontLib/BinaryStream.php
+++ b/src/FontLib/BinaryStream.php
@@ -106,7 +106,7 @@ public static function getTempFile($allow_memory = true) {
       $f = fopen("php://temp", "rb+");
     }
     else {
-      $f = fopen(tempnam(sys_get_temp_dir(), "fnt"), "rb+");
+      $f = tmpfile();
     }
 
     return $f;