diff --git a/reference/filesystem/functions/tempnam.xml b/reference/filesystem/functions/tempnam.xml
index 01adaa12ce..8b6432f503 100644
--- a/reference/filesystem/functions/tempnam.xml
+++ b/reference/filesystem/functions/tempnam.xml
@@ -41,7 +41,8 @@
       </para>
       <note>
        <simpara>
-        Windows uses only the first three characters of prefix.
+        Only the first 63 characters of the prefix are used.
+        Windows even uses only the first three characters of the prefix.
        </simpara>
       </note>
      </listitem>