diff --git a/libc/include/sys/shm.h b/libc/include/sys/shm.h
index a3f84d3..9d58046 100644
--- a/libc/include/sys/shm.h
+++ b/libc/include/sys/shm.h
@@ -47,11 +47,11 @@
 typedef unsigned long shmatt_t;
 
 /** Not useful on Android; disallowed by SELinux. */
-void* shmat(int __shm_id, const void* __addr, int __flags) __INTRODUCED_IN(26);
+void* _Nonnull shmat(int __shm_id, const void* _Nullable __addr, int __flags) __INTRODUCED_IN(26);
 /** Not useful on Android; disallowed by SELinux. */
-int shmctl(int __shm_id, int __cmd, struct shmid_ds* __buf) __INTRODUCED_IN(26);
+int shmctl(int __shm_id, int __cmd, struct shmid_ds* _Nullable __buf) __INTRODUCED_IN(26);
 /** Not useful on Android; disallowed by SELinux. */
-int shmdt(const void* __addr) __INTRODUCED_IN(26);
+int shmdt(const void* _Nonnull __addr) __INTRODUCED_IN(26);
 /** Not useful on Android; disallowed by SELinux. */
 int shmget(key_t __key, size_t __size, int __flags) __INTRODUCED_IN(26);