You can download the ready-compiled DLL here.

https://support.automation.siemens.com/livelinksupport/vorlagen/grafik/disk_35.gif T1_C.zip ( 17 KB )

extern "C" __declspec (dllexport) int aufruf1 (int a);

#include <stdio.h>
#include <windows.h>
FILE *h_test;
FILE *h_trace;
extern "C" __declspec (dllexport) int aufruf1(int a)
{
h_test= fopen ("C:/temp/test_dll.txt","a");
if (h_test)
{
fprintf(h_test, "Function 'aufruf1' was called!n");
fclose (h_test );
}
a+=100;
return a;
};

N.B.

• The DLL must be created without debug information.
• All the DLL functions used in WinCC must be specified in the corresponding syntax at the beginning of the DLL (see the first line in the sample DLL "T1_C.dll").
• In order to be able to use the DLL functions, they must be incorporated in the action or function in WinCC at the beginning with the "#pragma code" instruction.

• var1 (signed 32-bit value)
• result (signed 32-bit value)

Create the following C script on the "mouse-click" event of a button:

#include "apdefap.h"
void OnClick(char* lpszPictureName, char* lpszObjectName, char* lpszPropertyName)
{
#pragma code ("c:/temp/T1_C.dll")
int aufruf1(int a);
#pragma code ()

int value;
value = GetTagDouble("var1"); //Return-Type: double
SetTagDouble("result",aufruf1(value)); //Return-Type: BOOL
}

https://support.automation.siemens.com/WW/llisapi.dll/csfetch/8301801/8301801_WinCC_DLL_einbinden_01.gif
Fig. 01