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Entry type: FAQ Entry ID: 850216, Entry date: 11/08/2010

How do you call a user-specific Help in a WinCC project?

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In WinCC you can use an API call to call a user-specific Help. With "fuCommand" you can branch to a specific topic. For this you create a new project function with the code below:

#pragma code("user32.dll")
BOOL WinHelpA(hwnd, lpszHelpFile, fuCommand, dwData);
#pragma code()
#define HELP_CONTENTS 0x0003L

void WinHelpApi()
HWND hwnd; /* handle of window requesting help */
char HelpFile[255];
UINT fuCommand; /* type of help */
DWORD dwData; /* additional data */
BOOL bRetVal;
LPCTSTR lpszHelp;

lpszHelp = HelpFile;
strcpy(HelpFile, "c:\\Win.95\\Help\\Calc.hlp");
hwnd = FindWindow("PDLRTisAliveAndWaitsForYou","WinCC-Runtime - ");
fuCommand = HELP_CONTENTS;
dwData = 0L;

bRetVal=WinHelpA((DWORD) hwnd,(DWORD) lpszHelp, fuCommand, dwData);

printf("hwnd: %d \r\n",hwnd);
printf("HelpFile: %s \r\n",HelpFile);
printf("bRetVal: %d \r\n",bRetVal);

In this example the "Help for Windows Pocket Computers" is opened. If you want to open a different Help file, replace the "HelpFile" string with the path of a different file. If the return value "bRetVal" is equal to 0, an error has occurred. You can now call this project function, for example, by clicking a button.

Here, we are talking about calling a Windows function. Detailed descriptions are given for instance in the documentation for Visual C++. This example is solely to demonstrate how to incorporate the call in WinCC.

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