diff --git a/sz/include/TightDataPointStorageD.h b/sz/include/TightDataPointStorageD.h
index f63c3da5..4fc5be82 100644
--- a/sz/include/TightDataPointStorageD.h
+++ b/sz/include/TightDataPointStorageD.h
@@ -66,7 +66,7 @@ void new_TightDataPointStorageD(TightDataPointStorageD **self,
 		double realPrecision, double medianValue, char reqLength, unsigned int intervals, 
 		unsigned char* pwrErrBoundBytes, size_t pwrErrBoundBytes_size, unsigned char radExpo);
 
-void new_TightDataPointStorageD2(TightDataPointStorageD **this, 
+void new_TightDataPointStorageD2(TightDataPointStorageD **self, 
 		size_t dataSeriesLength, size_t exactDataNum, 
 		int* type, unsigned char* exactMidBytes, size_t exactMidBytes_size,
 		unsigned char* leadNumIntArray,  //leadNumIntArray contains readable numbers....
diff --git a/sz/include/TightDataPointStorageF.h b/sz/include/TightDataPointStorageF.h
index 2ca67836..eca1717b 100644
--- a/sz/include/TightDataPointStorageF.h
+++ b/sz/include/TightDataPointStorageF.h
@@ -73,7 +73,7 @@ void new_TightDataPointStorageF(TightDataPointStorageF **self,
  * This function is designed for first-version of the point-wise relative error bound (developed by Sheng Di for TPDS18 paper)
  * 
  * */
-void new_TightDataPointStorageF2(TightDataPointStorageF **this,
+void new_TightDataPointStorageF2(TightDataPointStorageF **self,
 		size_t dataSeriesLength, size_t exactDataNum, 
 		int* type, unsigned char* exactMidBytes, size_t exactMidBytes_size,
 		unsigned char* leadNumIntArray,  //leadNumIntArray contains readable numbers....