diff --git a/src/IO/ADIOS/ADIOS2IOHandler.cpp b/src/IO/ADIOS/ADIOS2IOHandler.cpp
index 1349e3b1f4..a9af92e4a0 100644
--- a/src/IO/ADIOS/ADIOS2IOHandler.cpp
+++ b/src/IO/ADIOS/ADIOS2IOHandler.cpp
@@ -1824,6 +1824,7 @@ namespace detail
         auto defineAttribute =
             [&IO, &fullName, &modifiable, &impl](auto const &...args) {
 #if openPMD_HAS_ADIOS_2_9
+                (void)impl;
                 auto attr = IO.DefineAttribute(
                     fullName,
                     args...,