diff --git a/include/sched.h b/include/sched.h
index 2d4f301c9718..e03f076febb1 100644
--- a/include/sched.h
+++ b/include/sched.h
@@ -41,7 +41,7 @@ typedef struct _cpuset cpu_set_t;
 __BEGIN_DECLS
 #if __BSD_VISIBLE
 int sched_getaffinity(pid_t pid, size_t cpusetsz, cpuset_t *cpuset);
-int sched_setaffinity(int pid, size_t cpusetsz, const cpuset_t *cpuset);
+int sched_setaffinity(pid_t pid, size_t cpusetsz, const cpuset_t *cpuset);
 int sched_getcpu(void);
 #endif /* __BSD_VISIBLE */
 __END_DECLS