Open chm files

I havewritten this function:

#include "apdefap.h"

#pragma code ("hhctrl.ocx")
HWND HtmlHelpA(HWND hwnd, LPCSTR lpHelpFile, DWORD wCommand, LPCSTR dwData);
#pragma code()

#define HH_DISPLAY_TOPIC 0

void HelpOnLine(char * file, char * topic)
{

HWND hwnd; /* handle of window requesting help */

hwnd = FindWindow("PDLRTisAliveAndWaitsForYou","WinCC Runtime - ");
HtmlHelpA(hwnd, file, HH_DISPLAY_TOPIC, topic);

}

I call the function in a button script with this syntax:

HelpOnLine("C:\\MyHelp.chm", "MyTopic.htm");

It works, but now I have another problem: if I launch my help file and then I come back to WinCC without closing it, I can't take the help in foreground.

I found it, the problem was the Class Name of the window: it wasn' correct.
This is the funcion I wrote, it works correctly.

#include "apdefap.h"

#pragma code ("hhctrl.ocx")
HWND HtmlHelpA(HWND hwnd, LPCSTR lpHelpFile, DWORD wCommand, LPCSTR dwData);
#pragma code()

#define HH_DISPLAY_TOPIC 0

void HelpOnLine(char * file, char * topic)
{

HWND hwnd; /* handle of window requesting help */
HWND hwndhelp;

hwnd = FindWindow("PDLRTisAliveAndWaitsForYou","WinCC Runtime - ");
HtmlHelpA(hwnd, file, HH_DISPLAY_TOPIC, topic);

hwndhelp=FindWindow("HH Parent", NULL);
SetForegroundWindow(hwndhelp);

}