rt_device_write/read return data type as rt_ssize_t

rt_ssize_t can give negative error code, which follows the unix style correctly

1 files changed, 2 insertions, 2 deletions

diff --git a/documentation/device/device.md b/documentation/device/device.md
index 33887d3fe6..2f24f61304 100644
--- a/documentation/device/device.md
+++ b/documentation/device/device.md
@@ -120,8 +120,8 @@ struct rt_device_ops
     rt_err_t  (*init)   (rt_device_t dev);
     rt_err_t  (*open)   (rt_device_t dev, rt_uint16_t oflag);
     rt_err_t  (*close)  (rt_device_t dev);
-    rt_size_t (*read)   (rt_device_t dev, rt_off_t pos, void *buffer, rt_size_t size);
-    rt_size_t (*write)  (rt_device_t dev, rt_off_t pos, const void *buffer, rt_size_t size);
+    rt_ssize_t (*read)  (rt_device_t dev, rt_off_t pos, void *buffer, rt_size_t size);
+    rt_ssize_t (*write) (rt_device_t dev, rt_off_t pos, const void *buffer, rt_size_t size);
     rt_err_t  (*control)(rt_device_t dev, int cmd, void *args);
 };