How to code? - Page 116

gorgoroth · #**1151** (**permalink**) 08-12-2008, 08:52 AM

Quote:

Originally Posted by gorgoroth

Hi everyone,

I've developed a set of functions to manage configuration settings from an EA.
Those functions are exported by a c++ DLL and each of the exported function has the __stdcall calling convetion requested my MQL4.

My problem arises when a function need to return a string to the EA.

Naturally the function cannot:
- return a pointer to a local variabile (variable goes out of scope)
- return a pointer to a dll global variable (problems with concurrent access)
- return a pointer to a heap allocated string (need functions to free memory to be called from the EA: I don't not like this approach)

So i resolved to pass a string and string size from the EA. Es:

Code:

string buffer;

GetString( buffer, 30 );

and from the c++ dll, something like this

Code:

void __stdcall GetString( LPTSTR buffer, int BufSize )
{
    // Read a string from a some source
    ....
    // -1 to take into account the terminating null character
    StringCchCopy( buffer, BufSize-1, ReadStringFromASource );
}

Here starts the weird behaviour of MQL managing strings returned from a DLL.

using the following code:

Code:

string buffer;
GetString( buffer, 30 );

the first time buffer contains the right string. A first question arises: buffer is not initialized but after calling GetString it contains the string returned. I have to suppose that MQL allocates space for a string variable when it's declared.

Next time GetString() is called the string returned seems to be truncated to the length-1 of the previous string length and not resetted as expected because of the 'string buffer;' statement.

Tried even:

Code:

string buffer = "                              "; // 'allocate' 30 blank characters
GetString( buffer, StringLen(buffer) );

but after the first time, when the execution returns to this code, the assignment of buffer does not work any more and buffer still contains the previous read string, and it seems it can only contains the number of characters of his content.

At first I have thought that the null character is not handled very well by MQL and modified the c++ code like this ...

Code:

CopyMemory( buffer, ReadStringFromASource, min(BufferSize,ReadStringFromASourceLength) );

and not adding the terminating null character.

But when called from MQL, no string at all is returning.

Has someone an answer ?

No one has problems returning string from DLLs ?

antone · #**1152** (**permalink**) 08-12-2008, 11:29 AM

I need help..

Can anyone show me a code? to attach to my EA..

One order per signal.. cause sometimes i have 3 signal cause of different TF.. i want all signal to open..

or a code that would take one order per bar but each Timeframe attach to one EA.. don't want to open alot of chart..

matrixebiz · #**1153** (**permalink**) 08-12-2008, 12:35 PM

What is wrong with my BuyStop?

Code:

ticket=OrderSend(Symbol(),OP_BUYSTOP,Lots,Ask+Distance*Point,Slippage,Bid-Distance-StopLoss*Point,Ask+Distance+TakeProfit*Point,"",MagicNumber,0,Blue);

antone · #**1154** (**permalink**) 08-12-2008, 01:11 PM

Quote:

Originally Posted by matrixebiz

What is wrong with my BuyStop?

Code:

ticket=OrderSend(Symbol(),OP_BUYSTOP,Lots,Ask+Distance*Point,Slippage,Bid-Distance-StopLoss*Point,Ask+Distance+TakeProfit*Point,"",MagicNumber,0,Blue);

your Stop lose and Take profit..

you should also add *point to your distance before adding it..

OR

Bid-((Distance-StopLoss)*Point),Ask+((Distance+TakeProfit)*Point)

FerruFx · #**1155** (**permalink**) 08-12-2008, 04:47 PM

Quote:

Originally Posted by matrixebiz

What is the difference between a Limit order and a Stop order?
Thanks

Here's the MT4 platform help file:

Quote:

Pending Order
Pending order is the client's commitment to the brokerage company to buy or sell a security at a pre-defined price in the future. This type of orders is used for opening of a trade position provided the future quotes reach the pre-defined level. There are four types of pending orders available in the terminal:

Buy Limit — buy provided the future "ASK" price is equal to the pre-defined value. The current price level is higher than the value of the placed order. Orders of this type are usually placed in anticipation of that the security price, having fallen to a certain level, will increase;

Buy Stop — buy provided the future "ASK" price is equal to the pre-defined value. The current price level is lower than the value of the placed order. Orders of this type are usually placed in anticipation of that the security price, having reached a certain level, will keep on increasing;

Sell Limit — sell provided the future "BID" price is equal to the pre-defined value. The current price level is lower than the value of the placed order. Orders of this type are usually placed in anticipation of that the security price, having increased to a certain level, will fall;

Sell Stop — sell provided the future "BID" price is equal to the pre-defined value. The current price level is higher than the value of the placed order. Orders of this type are usually placed in anticipation of that the security price, having reached a certain level, will keep on falling.

Hope that helps.

FerruFx

ichanz · #**1156** (**permalink**) 08-12-2008, 05:36 PM

Hi CodersGuru, Could you please let me know how to code script or EA for OP_SELL or OP_BUY for several pairs simultaneously at nearly same time.

For Instance : I would like to open BUY or SELL EURUSD and USDJPY at the same time.

Thank you

willmalou · #**1157** (**permalink**) 08-13-2008, 01:35 AM

This seems to be simple to code but my trades do not close when they are supposed to.
In this example trades should close at the cross of the lower time frame.

if (CloseSell1_1 > CloseSell1_2) Order = SIGNAL_CLOSESELL;

takis76 · #**1158** (**permalink**) 08-13-2008, 01:20 PM

Hi ,

I am here again and as noob , I am asking , how could I create a trailing stop code.

Code:

//+------------------------------------------------------------------+
//|                                                 TAKIS EA 007.mq4 |
//|                                   Copyright © 2008, Takis76 bots |
//|                                                                  |
//+------------------------------------------------------------------+
#property copyright "Copyright © 2008, Takis76 bots"
#property link      ""

//---- input parameters
extern double    Lots=0.01;


   int my_bars;
   string my_string;
   string my_string_mesos_oros;
   string my_string_timi_high;
   string my_string_timi_tora;

   double pinakas_timon[5];
   double mesos_oros;
   int orders;
   double StopLoss=10;
   int ticket;
   double TakeProfit=10;
   int MagicNumber=55555;
   int ypologisa_ton_meso_oro=0;   


   double timi_tora;
   double timi_high;
   double timi_open;
   
   int xronos;
//+------------------------------------------------------------------+
//| expert initialization function                                   |
//+------------------------------------------------------------------+
int init()
  {
//----
   
//----
   return(0);
  }
//+------------------------------------------------------------------+
//| expert deinitialization function                                 |
//+------------------------------------------------------------------+
int deinit()
  {
//----
   
//----
   return(0);
  }
//+------------------------------------------------------------------+
//| expert start function                                            |
//+------------------------------------------------------------------+
int start()
  {
//----

   
   my_bars=Bars;
   my_string=DoubleToStr(my_bars, 0);

   
   ObjectCreate("Show_Bars", OBJ_LABEL, 0, 0, 0);
   ObjectSetText("Show_Bars", my_string, 12, "Arial", Red);
   ObjectSet("Show_Bars", OBJPROP_CORNER, 0);
   ObjectSet("Show_Bars", OBJPROP_XDISTANCE, 1);
   ObjectSet("Show_Bars", OBJPROP_YDISTANCE, 10);
   
   
   //if (ypologisa_ton_meso_oro<6)
   //{
   mesos_oros=pinakas_timon[0]+pinakas_timon[1]+pinakas_timon[2]+pinakas_timon[3]+pinakas_timon[4]+pinakas_timon[5]/5;
   pinakas_timon[0]=Low[0];
   pinakas_timon[1]=Low[-1];
   pinakas_timon[2]=Low[-2];
   pinakas_timon[3]=Low[-3];
   pinakas_timon[4]=Low[-4];
   my_string_mesos_oros=DoubleToStr(mesos_oros, 4);
   //ypologisa_ton_meso_oro++;
   
   //}
   
   
   ObjectCreate("Mesi_Timi", OBJ_LABEL, 0, 0, 0);
   ObjectSetText("Mesi_Timi", my_string_mesos_oros, 12, "Arial", LightGreen);
   ObjectSet("Mesi_Timi", OBJPROP_CORNER, 0);
   ObjectSet("Mesi_Timi", OBJPROP_XDISTANCE, 1);
   ObjectSet("Mesi_Timi", OBJPROP_YDISTANCE, 25);





   
   timi_tora=Bid;
   timi_high=High[1];
   timi_open=Open[1];
   
   orders=OrdersTotal();
   
   //if (High[0]<(High[1]+High[2]+High[3]+High[4]+High[5]/5)*0.0099 && orders<1)
   if (High[0]<High[1] && orders<1)
   {
       //ticket=OrderSend(Symbol(),OP_BUY,Lots,(Ask),3,Ask-StopLoss*Point,Ask+TakeProfit*Point,"My order comment",MagicNumber,0,Green);
         
         ticket=OrderSend(Symbol(),OP_SELLLIMIT,Lots,(High[0]),3,Bid+StopLoss*Point,Bid-TakeProfit*Point,"My order comment",MagicNumber,0,Red);
   
      PlaySound("alert.wav");
   }
   if (orders>0)
   {
   
   //OrderModify(ticket,-1,Bid+StopLoss*Point,Low[0],0,White);
   }



   my_string_timi_high=DoubleToStr(timi_high, 4);

   ObjectCreate("Timi_High", OBJ_LABEL, 0, 0, 0);
   ObjectSetText("Timi_High", my_string_timi_high, 12, "Arial", LightBlue);
   ObjectSet("Timi_High", OBJPROP_CORNER, 0);
   ObjectSet("Timi_High", OBJPROP_XDISTANCE, 1);
   ObjectSet("Timi_High", OBJPROP_YDISTANCE, 50);


   my_string_timi_tora=DoubleToStr(timi_tora, 4);

   ObjectCreate("Timi_Tora", OBJ_LABEL, 0, 0, 0);
   ObjectSetText("Timi_Tora", my_string_timi_tora, 12, "Arial", LightBlue);
   ObjectSet("Timi_Tora", OBJPROP_CORNER, 0);
   ObjectSet("Timi_Tora", OBJPROP_XDISTANCE, 60);
   ObjectSet("Timi_Tora", OBJPROP_YDISTANCE, 50);
   
   
//----
   return(0);
  }
//+------------------------------------------------------------------+

As you see , this is my code of my expert Advisor.
Some variables are in greek.

Timi_Tora: -> Price_Now
my_string_timi_tora: -> The string of Price_Now
Mesi_Timi: -> Average_Price
my_string_mesos_oros:-> My string of Average
pinakas_timon[5]:-> Table of Variables
mesos_oros:-> Average
ypologisa_ton_meso_oro:->I calsulated the average
timi_high:-> Price High
timi_open:-> Price Open
xronos:-> Chronos

I put some english translate to my greek variables.

This expert advisor , Compares the high of the previously bar with the high of the current bar.
If the current bar with index[0] is lower than the previously bar , index[1] then I am opening one sell order.

Most of times the order is lower At least on pip of the previously , because as a high of this bar , have big change to go below at least one pip.

I have put 10 pips as take profit but some times the value reach the 9 pips and the order does not establish.

So some trailing ston need to wost time to take one pip profit.

This code is working with H1 Time Period
How do I do that?

This code working with H1 Time Period

Thank you very much.

I made some changes in another code...

And I had abnormal results , I backtest it from 1999 to 2007 and it made this Idea , about four hundred trilion dolars.
Then after 2007 program got crazy and drop OrderSend Error 138 .

matrixebiz · #**1159** (**permalink**) 08-13-2008, 02:30 PM

Hello, what code can I use to check if any Pending orders are open and close them at a specific time?

Thank you

takis76 · #**1160** (**permalink**) 08-13-2008, 08:12 PM

This Function will close all open trades.

Code:

      int orders = OrdersTotal();

void CloseAll()
{
      
      if (orders>0)
      {
      
         for (int cnt = 0 ; cnt < orders ; cnt++)
         {
            OrderSelect(0,SELECT_BY_POS,MODE_TRADES);
            if (OrderMagicNumber() == MagicNumber)
               if(OrderType()==OP_BUY)
               OrderClose(OrderTicket(),OrderLots(),Bid,3,  Violet);
               if(OrderType()==OP_SELL)   
               OrderClose(OrderTicket(),OrderLots(),Ask,3,  Violet);
               if(OrderType()==OP_BUYLIMIT)
               OrderDelete(ticket,Black);
               if(OrderType()==OP_SELLLIMIT)
               OrderDelete(ticket,Black);
         }
         
      }
      
}