diff --git a/src/ShimLib/ShimLib.h b/src/ShimLib/ShimLib.h
index 6c54e2d..917ab56 100644
--- a/src/ShimLib/ShimLib.h
+++ b/src/ShimLib/ShimLib.h
@@ -4,53 +4,48 @@
 
 #ifndef GUI_SHIMLIB_H
 #define GUI_SHIMLIB_H
-#ifdef __CPLUSPLUS
+#ifdef __cplusplus
 extern "C"{
 #endif
-typedef enum
-{
+typedef enum {
     BUSY,// device is preparing for scan
     READY,// device is ready for scan
     SCANING,// device is doing scan
     ERROR// some device inner error are occured
-}DeviceStatus;
+} DeviceStatus;
 
-typedef struct StatusInfo
-{
+typedef struct StatusInfo {
     DeviceStatus status;// a enum represent device current status
     float progress;// percent value of operation
-}StatusInfo;
-
+} StatusInfo;
 
 
 //3 kinds of scan action
-typedef enum
-{
+typedef enum {
     SCAN,// Start scan action
     PREVIEW_SCAN,// Start preview scan action
     STOP,// Stop current scan
-}ScanAction;
+} ScanAction;
 
 //kinds of device information
-typedef enum
-{
+typedef enum {
     MEAN_TEMPERATURE
-}DeviceInfo;
+} DeviceInfo;
 
-int InitLib(void(*)(const char * msg));
+extern int InitLib(void(*)(const char *msg));
 
-int ScanControl(ScanAction actionType);
+extern int ScanControl(ScanAction actionType);
 
-StatusInfo GetStatus();
+extern StatusInfo GetStatus();
 
-int SetScanInf(const char * jsonString);
+extern int SetScanInf(const char *jsonString);
 
-const char * GetPreviewData();
+extern const char *GetPreviewData();
 
-const char * GetDeviceInf(DeviceInfo infoType);
+extern const char *GetDeviceInf(DeviceInfo infoType);
 
-#ifdef __CPLUSPLUS
-}
+#ifdef __cplusplus
+};
 #endif
 
 #endif //GUI_SHIMLIB_H