C-Script for time & date sync with WinCC 6.0

I don't really understand C. But because I understand Visual Basic a little bit, I think it can be understood.

what means: return 0, GetTagBitWait, #pragma code ("kernel32.dll"); can someone explain a bit how this simple code works ?
Oven_3_Flag is cyclic triggered hourly.

wgy this line is needed: SetTagBitWait("Oven_3_Flag", TRUE);





#include "apdefap.h"
int gscAction( void )
{
#pragma code ("kernel32.dll");
void GetLocalTime (SYSTEMTIME *lpst);
#pragma code ();
SYSTEMTIME time;
if(GetTagBitWait("Oven_3_Flag")==0)
{
GetLocalTime (&time);
SetTagByteWait("Oven_3_Year", (BYTE)(time.wYear-2000));
SetTagWordWait("Oven_3_Month", time.wMonth);
SetTagWordWait("Oven_3_Day", time.wDay);
SetTagWordWait("Oven_3_Hour", time.wHour);
SetTagWordWait("Oven_3_Minute", time.wMinute);
SetTagWordWait("Oven_3_Second", time.wSecond);
SetTagBitWait("Oven_3_Flag", TRUE);
}
return 0;
}

OK, it's been a while but here goes:

1) Return 0 means the function returns 0 to the calling application if it completes successfully. Often numbers other than zero are used to indicate a problem to the calling function.

2) "pragma" means a compiler-specific option. In this case, it looks like 32-bit Window specific options have been turned on. This may mean your long integers are all 64 rather than 32bit, for example.

3) What the code is doing is making system call to get a pointer to the system time object when the Oven_3_flag is equal to 0. Once a reference to this object (i.e. an address) is returned, the time struct members are accessed to copy their values to the appropriate tags.

Note that it is easy to get confused between the way GetLocalTime is declared with an argument that is an pointer, how it is called with an reference. Both are types of pointer to memory that are interchangeable here (a reference is just a fixed pointer).

The bracketed (byte) keyword indicates the data is being cast into the byte format.

Hope that helps... best guess from uni projects

Adding to Binaural:

When Oven_3_flag is zero it is set back to one and current date is copied into Oven_3's date structure. Some other processing must be involved which reads the Oven_3 date data and sets Oven_3_flag back to zero.