diff --git a/tools/c-index-test/c-index-test.c b/tools/c-index-test/c-index-test.c
index 7376495..1ad4826 100644
--- a/tools/c-index-test/c-index-test.c
+++ b/tools/c-index-test/c-index-test.c
@@ -64,7 +64,7 @@
           Ref = clang_getCursor(Unit, clang_getCursorSource(Cursor),
                                 curLine, curColumn);
           if (Ref.kind == CXCursor_NoDeclFound) {
-            // Nothing found here; that's fine.
+            /* Nothing found here; that's fine. */
           } else if (Ref.kind != CXCursor_FunctionDecl) {
             printf("// CHECK: %s:%d:%d: ", basename(clang_getCursorSource(Ref)),
                                              curLine, curColumn);