diff --git a/libc/private/bionic_tls.h b/libc/private/bionic_tls.h
index d15b1ca..9ea3647 100644
--- a/libc/private/bionic_tls.h
+++ b/libc/private/bionic_tls.h
@@ -113,7 +113,7 @@
 __END_DECLS
 
 #if defined(__cplusplus)
-struct KernelArgumentBlock;
+class KernelArgumentBlock;
 extern __LIBC_HIDDEN__ void __libc_init_tls(KernelArgumentBlock& args);
 #endif