# SymbolInfoDouble

[Reference](https://docs.mql4.com/marketinformation/symbolinfodouble);

Returns the corresponding property of a specified symbol. There are 2 variants of the function.

1. Immediately returns the property value.

```mq4
double  SymbolInfoDouble(
   string                   name,       // symbol
   ENUM_SYMBOL_INFO_DOUBLE  prop_id     // identifier of the property
   );
```

2. Returns true or false depending on whether a function is successfully performed. In case of success, the value of the property is placed into a recipient variable, passed by reference by the last parameter.

```mq4
bool  SymbolInfoDouble(
   string                   name,       // symbol
   ENUM_SYMBOL_INFO_DOUBLE  prop_id,    // identifier of the property
   double&                  double_var  // here we accept the property value
   );
```

Parameters

name

[in] Symbol name.

prop_id

[in] Identifier of a symbol property. The value can be one of the values of the ENUM_SYMBOL_INFO_DOUBLE enumeration.

double_var

[out] Variable of double type receiving the value of the requested property.

Return Value

The value of double type. In case of execution failure, information about the error can be obtained using GetLastError() function:

4106 — symbol is not selected in "Market Watch" (not found in the list of available ones),
4051 — invalid identifier of a symbol property,
4024 — internal error.
Note

It is recommended to use SymbolInfoTick() if the function is used for getting information about the last tick. It may well be that not a single quote has appeared yet since the terminal is connected to a trading account. In such a case, the requested value will be indefinite.

In most cases, it is enough to use SymbolInfoTick() function allowing a user to receive the values of Ask, Bid, Last, Volume and the time of the last tick's arrival during a single call.

Example:

```mq4
void OnTick()
  {
//--- obtain spread from the symbol properties
   bool spreadfloat=SymbolInfoInteger(Symbol(),SYMBOL_SPREAD_FLOAT);
   string comm=StringFormat("Spread %s = %I64d points\r\n",
                            spreadfloat?"floating":"fixed",
                            SymbolInfoInteger(Symbol(),SYMBOL_SPREAD));
//--- now let's calculate the spread by ourselves
   double ask=SymbolInfoDouble(Symbol(),SYMBOL_ASK);
   double bid=SymbolInfoDouble(Symbol(),SYMBOL_BID);
   double spread=ask-bid;
   int spread_points=(int)MathRound(spread/SymbolInfoDouble(Symbol(),SYMBOL_POINT));
   comm=comm+"Calculated spread = "+(string)spread_points+" points";
   Comment(comm);
  }
```