diff --git a/libc/include/sys/ipc.h b/libc/include/sys/ipc.h
index 2e2b8cf..f557ce5 100644
--- a/libc/include/sys/ipc.h
+++ b/libc/include/sys/ipc.h
@@ -47,7 +47,7 @@
 __BEGIN_DECLS
 
 /**
- * [ftok(3)](http://man7.org/linux/man-pages/man3/ftok.3.html) converts a path and id to a
+ * [ftok(3)](https://man7.org/linux/man-pages/man3/ftok.3.html) converts a path and id to a
  * System V IPC key.
  *
  * Returns a key on success, and returns -1 and sets `errno` on failure.