diff --git a/libc/include/sys/signalfd.h b/libc/include/sys/signalfd.h
index 1e4d464..315622c 100644
--- a/libc/include/sys/signalfd.h
+++ b/libc/include/sys/signalfd.h
@@ -36,8 +36,8 @@
 
 __BEGIN_DECLS
 
-int signalfd(int fd, const sigset_t* mask, int flags) __INTRODUCED_IN(18);
+int signalfd(int __fd, const sigset_t* __mask, int __flags) __INTRODUCED_IN(18);
 
 __END_DECLS
 
-#endif /* _SYS_SIGNALFD_H */
+#endif