diff --git a/libcxx/test/std/utilities/format/format.formatter/format.parse.ctx/check_arg_id.pass.cpp b/libcxx/test/std/utilities/format/format.formatter/format.parse.ctx/check_arg_id.pass.cpp
--- a/libcxx/test/std/utilities/format/format.formatter/format.parse.ctx/check_arg_id.pass.cpp
+++ b/libcxx/test/std/utilities/format/format.formatter/format.parse.ctx/check_arg_id.pass.cpp
@@ -39,8 +39,12 @@
       context.check_arg_id(0);
       assert(false);
     } catch (const std::format_error& e) {
+#ifdef _LIBCPP_VERSION
       assert(strcmp(e.what(), "Using manual argument numbering in automatic "
                               "argument numbering mode") == 0);
+#else
+      (void)e;
+#endif
       return;
     }
     assert(false);
diff --git a/libcxx/test/std/utilities/format/format.formatter/format.parse.ctx/next_arg_id.pass.cpp b/libcxx/test/std/utilities/format/format.formatter/format.parse.ctx/next_arg_id.pass.cpp
--- a/libcxx/test/std/utilities/format/format.formatter/format.parse.ctx/next_arg_id.pass.cpp
+++ b/libcxx/test/std/utilities/format/format.formatter/format.parse.ctx/next_arg_id.pass.cpp
@@ -39,8 +39,12 @@
     context.next_arg_id();
     assert(false);
   } catch (const std::format_error& e) {
+#ifdef _LIBCPP_VERSION
     assert(strcmp(e.what(), "Using automatic argument numbering in manual "
                             "argument numbering mode") == 0);
+#else
+    (void)e;
+#endif
     return;
   }
   assert(false);