WinCC中有对字符串替换的C函数吗，谢谢，改如何实现。

在IO域中输入一个字符串后，AHU\\a中的a会随着字符串的值变化而变化。
char *a;
a=GetTagChat("TEXT1")

SetPropWord(lpszPictureName,"Control1","TrendIndex",0); //Return-Type: BOOL
SetPropChar(lpszPictureName,"Control1","TrendTagName","AHU\\a.RAT"); //Return-Type: BOOL
SetPropWord(lpszPictureName,"Control1","TrendIndex",1); //Return-Type: BOOL
SetPropChar(lpszPictureName,"Control1","TrendTagName","AHU\\a.RAH"); //Return-Type: BOOL
SetPropWord(lpszPictureName,"Control1","TrendIndex",2); //Return-Type: BOOL
SetPropChar(lpszPictureName,"Control1","TrendTagName","AHU\\a.SetTemp"); //Return-Type: BOOL
SetPropWord(lpszPictureName,"Control1","TrendIndex",3); //Return-Type: BOOL
SetPropChar(lpszPictureName,"Control1","TrendTagName","AHU\\a.SetHum"); //Return-Type: BOOL