diff --git a/man2/sigaltstack.2 b/man2/sigaltstack.2
index d78873d89..62284dbec 100644
--- a/man2/sigaltstack.2
+++ b/man2/sigaltstack.2
@@ -30,7 +30,8 @@ sigaltstack \- set and/or get signal stack context
 .nf
 .B #include <signal.h>
 .PP
-.BI "int sigaltstack(const stack_t *" ss ", stack_t *" old_ss );
+.BI "int sigaltstack(const stack_t *restrict " ss \
+", stack_t *restrict " old_ss );
 .fi
 .PP
 .RS -4