diff --git a/winsup/cygwin/include/pthread.h b/winsup/cygwin/include/pthread.h
index a55be5d40..6b7b6dde5 100644
--- a/winsup/cygwin/include/pthread.h
+++ b/winsup/cygwin/include/pthread.h
@@ -196,22 +196,19 @@ int pthread_spin_unlock (pthread_spinlock_t *);
 
 /* RW Locks */
 #if __XSI_VISIBLE >= 500 || __POSIX_VISIBLE >= 200112 || __cplusplus >= 201402L
-int pthread_rwlock_destroy (pthread_rwlock_t *rwlock);
-int pthread_rwlock_init (pthread_rwlock_t *rwlock, const pthread_rwlockattr_t *attr);
-int pthread_rwlock_rdlock (pthread_rwlock_t *rwlock);
-int pthread_rwlock_timedrdlock (pthread_rwlock_t *rwlock,
-				const struct timespec *abstime);
-int pthread_rwlock_tryrdlock (pthread_rwlock_t *rwlock);
-int pthread_rwlock_wrlock (pthread_rwlock_t *rwlock);
-int pthread_rwlock_timedwrlock (pthread_rwlock_t *rwlock,
-				const struct timespec *abstime);
-int pthread_rwlock_trywrlock (pthread_rwlock_t *rwlock);
-int pthread_rwlock_unlock (pthread_rwlock_t *rwlock);
-int pthread_rwlockattr_init (pthread_rwlockattr_t *rwlockattr);
-int pthread_rwlockattr_getpshared (const pthread_rwlockattr_t *attr,
-				   int *pshared);
-int pthread_rwlockattr_setpshared (pthread_rwlockattr_t *attr, int pshared);
-int pthread_rwlockattr_destroy (pthread_rwlockattr_t *rwlockattr);
+int pthread_rwlock_destroy (pthread_rwlock_t *);
+int pthread_rwlock_init (pthread_rwlock_t *, const pthread_rwlockattr_t *);
+int pthread_rwlock_rdlock (pthread_rwlock_t *);
+int pthread_rwlock_timedrdlock (pthread_rwlock_t *, const struct timespec *);
+int pthread_rwlock_tryrdlock (pthread_rwlock_t *);
+int pthread_rwlock_wrlock (pthread_rwlock_t *);
+int pthread_rwlock_timedwrlock (pthread_rwlock_t *, const struct timespec *);
+int pthread_rwlock_trywrlock (pthread_rwlock_t *);
+int pthread_rwlock_unlock (pthread_rwlock_t *);
+int pthread_rwlockattr_init (pthread_rwlockattr_t *);
+int pthread_rwlockattr_getpshared (const pthread_rwlockattr_t *, int *);
+int pthread_rwlockattr_setpshared (pthread_rwlockattr_t *, int);
+int pthread_rwlockattr_destroy (pthread_rwlockattr_t *);
 #endif
 
 int pthread_once (pthread_once_t *, void (*)(void));