including .dll file in MQL5\ Libraries folder

1. When posting code in forum, please use SRC button,  it makes your code much easier to read for other user who wants to help you

2. I bet you also don't know where yor EA, CI, and script is located. Use TerminalInfoString's TERMINAL_DATA_PATH, and if you use Vista/7, you'll find it in C:\Users\<use name>\AppData\Roaming\MetaQuotes\Terminal\<unix code>

3. Read this also How to Exchange Data: A DLL for MQL5 in 10 minutes.

Hello phi.nuts,  thanks for being such a good help.  I found the directory for MQL5/Libraries right where you said, and put the .dll file in there.  I read that article and tried to do exactly what it said, but in Codeblocks, not Visual C++.  When I tried to run the EA with the dll, I got an message in the experts log that said "DLL is not a 64 bit version."  So, I re-installed metatrader 5 , but using the 32 bit version.  Now when I try to run the EA with the DLL, I get two messages in the expert log.  "Cannot find fnCalculateSpeed in mql5_DLL.dll"  Is this because I am using codeblocks?  I really don't like visual C++.  Can you recommend a solution?

Here is the code.  Note that in codeblocks I changed the properties of the DLL project.  Under Build Targets,  I changed the output directory to    C:\Users\Joe\AppData\Roaming\MetaQuotes\Terminal\5D2A9C702A29311ED87B6AD8A346121B\MQL5\Libraries.  

I tried to follow all the steps in the article. 

//+------------------------------------------------------------------+
//|                                                  Calling_C++.mq5 |
//|                                                              Joe |
//|                                              www.uofgfinance.com |
//+------------------------------------------------------------------+
#property copyright "Joe"
#property link      "www.uofgfinance.com"
#property version   "1.00"

#import "mql5_DLL.dll"
int  fnCalculateSpeed(int &res1,double &res2);
#import

//+------------------------------------------------------------------+
//| Expert initialization function                                   |
//+------------------------------------------------------------------+
int OnInit()
  {
//---

//--- call
   int    speed=0;
   int    res_int=0;
   double res_double=0.0;

   speed=fnCalculateSpeed(res_int,res_double);
   Print("Time ",speed," msec, int: ",res_int," double: ",res_double);

  
  
  
//---
   return(0);
  }
//+------------------------------------------------------------------+
//| Expert deinitialization function                                 |
//+------------------------------------------------------------------+
void OnDeinit(const int reason)
  {
//---
   
  }
//+------------------------------------------------------------------+
//| Expert tick function                                             |
//+------------------------------------------------------------------+
void OnTick()
  {
//---
   MqlRates rt[2];
//--- call the Evolved Trader application only for first ticks of new bar
   if(CopyRates(_Symbol,_Period,0,2,rt)!=2)
     {
      Print("CopyRates of ",_Symbol," failed, no history");
      return;
     }
   if(rt[1].tick_volume>1) return;
   
  
   
   
   
  }

//And main.cpp for the codeblocks dll project  :

#include "main.h"
#include <iostream>
using namespace std;



_DLLAPI int __stdcall fnCalculateSpeed(int &res1,double &res2)
  {
   int    res_int=0;
   double res_double=0.0;
   int    start=GetTickCount();
//--- simple math calculations
   for(int i=0;i<=10000000;i++)
     {
      res_int+=i*i;
      res_int++;
      res_double+=i*i;
      res_double++;
     }
//--- set calculation results
   res1=res_int;
   res2=res_double;
//--- return calculation time
   return(GetTickCount()-start);
  }

_DLLAPI void __stdcall heyC()
{
    cout << "Hey!";
}

BOOL WINAPI DllMain(HINSTANCE hinstDLL, DWORD fdwReason, LPVOID lpvReserved)
{
    switch (fdwReason)
    {
        case DLL_PROCESS_ATTACH:
            // attach to process
            // return FALSE to fail DLL load
            break;

        case DLL_PROCESS_DETACH:
            // detach from process
            break;

        case DLL_THREAD_ATTACH:
            // attach to thread
            break;

        case DLL_THREAD_DETACH:
            // detach from thread
            break;
    }
    return TRUE; // succesful
}

#ifndef __MAIN_H__
#define __MAIN_H__

#include <windows.h>

#define _DLLAPI extern "C" __declspec(dllexport)

/*  To use this exported function of dll, include this header
 *  in your project.
 */

#ifdef BUILD_DLL
    #define DLL_EXPORT __declspec(dllexport)
#else
    #define DLL_EXPORT __declspec(dllimport)
#endif


#ifdef __cplusplus
extern "C"
{
#endif

_DLLAPI int __stdcall fnCalculateSpeed(int &res1,double &res2);
_DLLAPI void __stdcall heyC();

#ifdef __cplusplus
}
#endif

#endif // __MAIN_H__

Yes :). There is different way of calling function inside dll that was created using Code::Block compare with the one created by VS 2010.

I study your code but hate to tell you this, I kind busy right now so maybe you will get answer later :(.

Sorry :(.

Hope other forumer who use Code::Block also willing to help. 

Thank you phi.nuts!  I look forward to your answer later when you are not so busy.  I can see why you are so busy when looking at all the stuff to moderate on the forum.  Hopefully someone else comes along in the meantime.

  Update:  I am looking into the  stdcall and cdecl calling convention.  I read the docs on "Call of Imported Functions."

Awesome, I arrived at the same conclusion and I will try it when I get home.  The WinAPI part of the codeblocks DLL project should take care of it.  (just a normal function call)   Thanks again phi.nuts!   

Sure, why not, thanks!

I create plain C DLLs using the D programming language whenever i need more advanced functionality for MetaTrader. It's much easier with D to comunicate with MQL5 programs but it will be a good resource to have your C++ headers just in case.

Cheers.

Hey , so I sent instructions and code to my mate so he could use the dll too, I will copy and paste these same instruction/code here for your use if you need it.

Now if you ever want to use some C++ stuff in your EA's you can change around this example function

//+------------------------------------------------------------------+
//|                                                  Calling_C++.mq5 |
//|                                                              Joe |
//|                                              www.uofgfinance.com |
//+------------------------------------------------------------------+
#property copyright "Joe and Derek"
#property link      "www.uofgfinance.com"
#property version   "1.00"

#import "metatrader5_dll.dll"
int  SomeFunction(int &res1,double &res2);
#import

//+------------------------------------------------------------------+
//| Expert initialization function                                   |
//+------------------------------------------------------------------+
int OnInit()
  {
//---

//--- call
   int    speed=0;
   int    res_int=0;
   double res_double=0.0;

   speed=SomeFunction(res_int,res_double);
   Print("Time ",speed," msec, int: ",res_int," double: ",res_double);
   

  
  
  
//---
   return(0);
  }
//+------------------------------------------------------------------+
//| Expert deinitialization function                                 |
//+------------------------------------------------------------------+
void OnDeinit(const int reason)
  {
//---
   
  }
//+------------------------------------------------------------------+
//| Expert tick function                                             |
//+------------------------------------------------------------------+
void OnTick()
  {
//---
   MqlRates rt[2];
//--- call the Evolved Trader application only for first ticks of new bar
   if(CopyRates(_Symbol,_Period,0,2,rt)!=2)
     {
      Print("CopyRates of ",_Symbol," failed, no history");
      return;
     }
   if(rt[1].tick_volume>1) return;
   
  
   
   
   
  }

#ifndef __MAIN_H__
#define __MAIN_H__

#include <windows.h>

/*  To use this exported function of dll, include this header
 *  in your project.
 */

#ifdef BUILD_DLL
    #define DLL_EXPORT __declspec(dllexport)
#else
    #define DLL_EXPORT __declspec(dllimport)
#endif


#ifdef __cplusplus
extern "C"
{
#endif

void DLL_EXPORT fnFillArray(int *arr,const int arr_size);

#ifdef __cplusplus
}
#endif

#endif // __MAIN_H__