For WinCC scada and C the following syntax applies
GetTagBit("TagName");//Return-Type: BOOL
GetTagByte("TagName");//Return-Type: BYTE
GetTagChar("TagName");//Return-Type: char*
GetTagDouble("TagName");//Return-Type: double
GetTagDWord("TagName");//Return-Type: DWORD
GetTagFloat("TagName");//Return-Type: float
GetTagRaw("TagName",pValue,size);//Return-Type: BOOL
GetTagSByte("TagName");//Return-Type: char
GetTagSDWord("TagName");//Return-Type: long int
GetTagSWord("TagName");//Return-Type: short int
GetTagValue(lpdmVarKey,lpdmresult,lpdmError);//Return-Type BOOL
GetTagWord("TagName");//Return-Type: WORD
SetTagBit ("TagName", short int value);
SetTagByte ("TagName", BYTE value);
SetTagChar ("TagName", LPSTR value);
SetTagDouble ("TagName", double value);
SetTagDWord ("TagName", DWORD value);
SetTagFloat ("TagName", float value);
SetTagRaw ("TagName", BYTE* pValue, DWORD size);
SetTagSByte ("TagName", char value);
SetTagSDWord ("TagName", long int value);
SetTagSWord ("TagName", short int value);
SetTagValue (LPDM_VARKEY lpdmVarKey, LPVARIANT lpdmValue, PDWORD dwState, LPCMN_ERROR lpdmError);
SetTagWord ("TagName", WORD value);