diff --git a/include/unistd.h b/include/unistd.h
index 0329122f7e7c..ef77133d0ba5 100644
--- a/include/unistd.h
+++ b/include/unistd.h
@@ -327,9 +327,9 @@ int	 close(int);
 void	 closefrom(int);
 int	 dup(int);
 int	 dup2(int, int);
-int	 execl(const char *, const char *, ...);
+int	 execl(const char *, const char *, ...) __sentinel;
 int	 execle(const char *, const char *, ...);
-int	 execlp(const char *, const char *, ...);
+int	 execlp(const char *, const char *, ...) __sentinel;
 int	 execv(const char *, char * const *);
 int	 execve(const char *, char * const *, char * const *);
 int	 execvp(const char *, char * const *);