returns the execution policy.

There can be one and two ...

Check:

//+------------------------------------------------------------------+
//| проверяет разрешенность указанного режима заполнения             |
//+------------------------------------------------------------------+
bool IsFillingTypeAllowed(string symbol,int fill_type)
  {
//--- получим значение свойства, описывающего режим заполнения
   int filling=(int)SymbolInfoInteger(symbol,SYMBOL_FILLING_MODE);
//--- вернем true, если режим fill_type разрешен
   return((filling&fill_type)==fill_type);
  }

a bit check is needed. for example:

ENUM_ORDER_TYPE_FILLING OrderTypeFilling(const string symbol)
{
 int FillingFlags = (int)SymbolInfoInteger(symbol, SYMBOL_FILLING_MODE);
 
 if((FillingFlags & SYMBOL_FILLING_FOK) == SYMBOL_FILLING_FOK)
                                     return ORDER_FILLING_FOK;
 else 
 if((FillingFlags & SYMBOL_FILLING_IOC) == SYMBOL_FILLING_IOC)
                                     return ORDER_FILLING_IOC;
 else
                                     return ORDER_FILLING_RETURN;
}

if(x>0.0)
break;
if(x<0.0)
y++;

Why is this not the same as return. Return will return control to the calling program, which proceeds to the next operator. Break forces a transition to the next operator. Can the calling program ignore the next operator?

Give me a link to the documentation where this

if(x>0.0)
break;
if(x<0.0)
y++;

example ...

1. Don't try to take the code out of context.

2. Read the End Break Operator Help carefully.

3. Only after you have completed tasks 1 and 2 can you continue to ask questions.

iok is 2
fok is 1
gtc is 0

what then returns if ioc and fok

Example from CTrade trade class. First it is checked for'SYMBOL_FILLING_FOK', then for'SYMBOL_FILLING_IOC'.

//+------------------------------------------------------------------+
//| Set order filling type according to symbol filling mode          |
//+------------------------------------------------------------------+
bool CTrade::SetTypeFillingBySymbol(const string symbol)
  {
//--- get possible filling policy types by symbol
   uint filling=(uint)SymbolInfoInteger(symbol,SYMBOL_FILLING_MODE);
   if((filling&SYMBOL_FILLING_FOK)==SYMBOL_FILLING_FOK)
     {
      m_type_filling=ORDER_FILLING_FOK;
      return(true);
     }
   if((filling&SYMBOL_FILLING_IOC)==SYMBOL_FILLING_IOC)
     {
      m_type_filling=ORDER_FILLING_IOC;
      return(true);
     }
//---
   return(false);
  }

The check is performed by usingthe 'AND bitwise operation'.

Bitwise AND operation

The bitwise AND operation of the binary representations x and y. The value of the expression contains 1 (TRUE) in all bits where both x and y contain non-zero; and 0 (FALSE) in all other bits.

b = ((x & y) != 0);

Example:

   char a='a',b='b';
//--- операция И
   char c=a&b;
   Print("a = ",a,"  b = ",b);
   Print("a & b = ",c);
// Результат будет такой:
// a = 97   b = 98
// a & b = 96

More about bitwise operations.