MQL Program unexpectedly terminated - mql4

Question

I'm new to MQL language, so please correct me if I described something wrong.
I made an script by the script editor to place orders automatically. The program should be never stopped unless by manually termination. My code looks like that:
void onStart()
{
While(true)
{
Sleep(10000);
MakeOrder(....);//of course actual code is much more complicated
}
}
The only preset functions I use are trade functions, math functions and time functions.
The code works well for most of the times that can continue running at least for 48 hours, but sometimes it might unexpectedly stopped reporting deinit reason 4(which is the same exit code if I click stop button when debugging) within one hour after starting. It looks that MQL doesn't have try...catch module, and getting error in some coding lines won't stop it. I wonder what might have happened behind the termination? Or how can I ignore it, so at least the program can automatically restart?

Answer 1

You should check the OnTimer and OnTick functions.
And recommended to use IsStopped() in the While loop.
void onStart()
{
while(!IsStopped())
{
Sleep(10000);
MakeOrder(....);//of course actual code is much more complicated
}
}

Answer 2

Uninitialization Reason 4 is : chart has been closed. In MT4, you always need to run a script on a chart (window), so of course if this chart is close for any reason, your script will terminate. There is nothing you can do to prevent that.
As suggested, adding IsStopped() will terminate your loop (and script), so what you can do is to add some code after your loop to notify you the script is being terminated.
For example :
void OnStart()
{
//---
while(!IsStopped())
{
Sleep(10000);
//MakeOrder(....);//of course actual code is much more complicated
}
//---
if(UninitializeReason()==REASON_CHARTCLOSE)
{
string msg="Chart is closed and the script is terminated.";
Alert(msg);
SendNotification(msg);
}
}