diff --git a/include/nsyshid/hid.h b/include/nsyshid/hid.h
index 143c1b4..bce47c4 100644
--- a/include/nsyshid/hid.h
+++ b/include/nsyshid/hid.h
@@ -5,118 +5,146 @@
 extern "C" {
 #endif
 
-typedef struct
+typedef struct HIDClient HIDClient;
+typedef struct HIDDevice HIDDevice;
+
+typedef enum HIDAttachEvent
 {
-    uint32_t handle;
-    uint32_t physical_device_inst;
-    uint16_t vid;
-    uint16_t pid;
-    uint8_t interface_index;
-    uint8_t sub_class;
-    uint8_t protocol;
+   HID_DEVICE_ATTACH = 0,
+   HID_DEVICE_DETACH = 1,
+} HIDAttachEvent;
 
-    uint16_t max_packet_size_rx;
-    uint16_t max_packet_size_tx;
-} HIDDevice;
+typedef int32_t
+(*HIDAttachCallback)(HIDClient *client,
+                     HIDDevice *device,
+                     HIDAttachEvent attach);
 
-#define HID_DEVICE_DETACH   0
-#define HID_DEVICE_ATTACH   1
+typedef void
+(*HIDCallback)(uint32_t handle,
+               int32_t error,
+               uint8_t *buffer,
+               uint32_t bytesTransferred,
+               void *userContext);
 
-typedef struct _HIDClient HIDClient;
-
-typedef int32_t (*HIDAttachCallback)(HIDClient *p_hc,HIDDevice *p_hd,uint32_t attach);
-
-struct _HIDClient
+struct HIDDevice
 {
-    HIDClient *next;
-    HIDAttachCallback attach_cb;
+   uint32_t handle;
+   uint32_t physicalDeviceInst;
+   uint16_t vid;
+   uint16_t pid;
+   uint8_t interfaceIndex;
+   uint8_t subClass;
+   uint8_t protocol;
+   PADDING(1);
+   uint16_t maxPacketSizeRx;
+   uint16_t maxPacketSizeTx;
 };
+CHECK_OFFSET(HIDDevice, 0x00, handle);
+CHECK_OFFSET(HIDDevice, 0x04, physicalDeviceInst);
+CHECK_OFFSET(HIDDevice, 0x08, vid);
+CHECK_OFFSET(HIDDevice, 0x0A, pid);
+CHECK_OFFSET(HIDDevice, 0x0C, interfaceIndex);
+CHECK_OFFSET(HIDDevice, 0x0D, subClass);
+CHECK_OFFSET(HIDDevice, 0x0E, protocol);
+CHECK_OFFSET(HIDDevice, 0x10, maxPacketSizeRx);
+CHECK_OFFSET(HIDDevice, 0x12, maxPacketSizeTx);
+CHECK_SIZE(HIDDevice, 0x14);
+
+struct HIDClient
+{
+   HIDClient *next;
+   HIDAttachCallback attachCallback;
+};
+CHECK_OFFSET(HIDClient, 0x00, next);
+CHECK_OFFSET(HIDClient, 0x04, attachCallback);
+CHECK_SIZE(HIDClient, 0x08);
 
-typedef void  HIDCallback(uint32_t handle,int32_t error,uint8_t *p_buffer,uint32_t bytes_transferred,void *p_user);
 
 int32_t
-HIDSetup(void);
+HIDSetup();
 
 int32_t
-HIDTeardown(void);
+HIDTeardown();
 
 int32_t
-HIDAddClient(HIDClient *p_client, HIDAttachCallback attach_callback);
+HIDAddClient(HIDClient *client,
+             HIDAttachCallback attachCallback);
 
 int32_t
-HIDDelClient(HIDClient *p_client);
+HIDDelClient(HIDClient *client);
 
 int32_t
 HIDGetDescriptor(uint32_t handle,
-                 uint8_t descriptor_type,
-                 uint8_t descriptor_index,
-                 uint16_t language_id, 
-                 uint8_t *p_buffer, 
-                 uint32_t buffer_length, 
-                 HIDCallback hc, void *p_user);
+                 uint8_t descriptorType,
+                 uint8_t descriptorIndex,
+                 uint16_t languageId,
+                 uint8_t *buffer,
+                 uint32_t bufferLength,
+                 HIDCallback callback,
+                 void *userContext);
 
 int32_t
 HIDSetDescriptor(uint32_t handle,
-                 uint8_t descriptor_type,
-                 uint8_t descriptor_index, 
-                 uint16_t language_id, 
-                 uint8_t *p_buffer, 
-                 uint32_t buffer_length, 
-                 HIDCallback hc, 
-                 void *p_user);
+                 uint8_t descriptorType,
+                 uint8_t descriptorIndex,
+                 uint16_t languageId,
+                 uint8_t *buffer,
+                 uint32_t bufferLength,
+                 HIDCallback callback,
+                 void *userContext);
 
 int32_t
-HIDGetReport(uint32_t handle, 
-             uint8_t report_type, 
-             uint8_t report_id, 
-             uint8_t *p_buffer, 
-             uint32_t buffer_length, 
-             HIDCallback hc, 
-             void *p_user);
+HIDGetReport(uint32_t handle,
+             uint8_t reportType,
+             uint8_t reportId,
+             uint8_t *buffer,
+             uint32_t bufferLength,
+             HIDCallback callback,
+             void *userContext);
 
 int32_t
-HIDSetReport(uint32_t handle, 
-             uint8_t report_type, 
-             uint8_t report_id, 
-             uint8_t *p_buffer, 
-             uint32_t buffer_length, 
-             HIDCallback hc, 
-             void *p_user);
+HIDSetReport(uint32_t handle,
+             uint8_t reportType,
+             uint8_t reportId,
+             uint8_t *buffer,
+             uint32_t bufferLength,
+             HIDCallback callback,
+             void *userContext);
 
 int32_t
-HIDSetIdle(uint32_t handle, 
-           uint8_t interface_index,
-           uint8_t duration, 
-           HIDCallback hc, 
-           void *p_user);
+HIDSetIdle(uint32_t handle,
+           uint8_t interfaceIndex,
+           uint8_t duration,
+           HIDCallback callback,
+           void *userContext);
 
 int32_t
 HIDSetProtocol(uint32_t handle,
-               uint8_t interface_index,
-               uint8_t protocol, 
-               HIDCallback hc, 
-               void *p_user);
+               uint8_t interfaceIndex,
+               uint8_t protocol,
+               HIDCallback callback,
+               void *userContext);
 
 int32_t
 HIDGetProtocol(uint32_t handle,
-               uint8_t interface_index,
-               uint8_t * protocol, 
-               HIDCallback hc, 
-               void *p_user);
+               uint8_t interfaceIndex,
+               uint8_t *protocol,
+               HIDCallback callback,
+               void *userContext);
 
 int32_t
-HIDRead(uint32_t handle, 
-        uint8_t *p_buffer, 
-        uint32_t buffer_length, 
-        HIDCallback hc, 
-        void *p_user);
-        
+HIDRead(uint32_t handle,
+        uint8_t *buffer,
+        uint32_t bufferLength,
+        HIDCallback callback,
+        void *userContext);
+
 int32_t
-HIDWrite(uint32_t handle, 
-         uint8_t *p_buffer, 
-         uint32_t buffer_length, 
-         HIDCallback hc, 
-         void *p_user);
+HIDWrite(uint32_t handle,
+         uint8_t *buffer,
+         uint32_t bufferLength,
+         HIDCallback hc,
+         void *userContext);
 
 #ifdef __cplusplus
 }