How to make a subroutine?

I want to make a function that allways run in background.
I will use this code to check the buffers and generate messages to pull items for necessary locations from related stocking areas.
Where should I place this type of codes?

It should be do that in a cycle, for example every 5 seconds.
It will be very helpful if you can give an example code that executes something like:
...
start:
calculate x = necessary buffer - real buffer
if x>0 then generate message
wait 5 time unit
goto start
...
I'm quite new in Flexsim and also in C++, so sorry for the simple questions but I couldn't find the solution.

Thanks for your help.

Enver,

You would want to use a user event to do this. You can specify the start time and the repeat time. The only real complex issue that you are going to have in this is getting pointers to the buffers that you want to search. I would recommend making center port connections from all of the buffers to one particular object in the model (might even be a dummy object just for this purpose). Then create a Global Variable to that object. From there you could reference all of the buffers with the centerobject command.

Use the Tool drop down menu to get to the user events and global variables.

Good Luck,
Brandon