diff --git a/man3/strtok.3 b/man3/strtok.3
index 6db48b677..8058ff2fe 100644
--- a/man3/strtok.3
+++ b/man3/strtok.3
@@ -36,8 +36,9 @@ strtok, strtok_r \- extract tokens from strings
 .nf
 .B #include <string.h>
 .PP
-.BI "char *strtok(char *" str ", const char *" delim );
-.BI "char *strtok_r(char *" str ", const char *" delim ", char **" saveptr );
+.BI "char *strtok(char *restrict " str ", const char *restrict " delim );
+.BI "char *strtok_r(char *restrict " str ", const char *restrict " delim ,
+.BI "               char **restrict " saveptr );
 .fi
 .PP
 .RS -4