Conditional compilation for include ?

[Lorentzos Roussos]

Is there a way method A would work ? 

(to include a library if its not included already if it is required)

#property version   "1.00"
#property strict
#include <Canvas\Canvas.mqh>
//A :
#ifdef CCanvas
string message_from_a="CANVAS IS INCLUDED";
#endif
#ifndef CCanvas
string message_from_a="CANVAS SHOULD BE INCLUDED";
#endif
//B : 
#ifdef XRGB
string message_from_b="CANVAS IS INCLUDED";
#endif 
#ifndef XRGB
string message_from_b="CANVAS SHOULD BE INCLUDED";
#endif
//+------------------------------------------------------------------+
//| Expert initialization function                                   |
//+------------------------------------------------------------------+
int OnInit()
  {
  Alert("Message from A : "+message_from_a+"\nMessage from B : "+message_from_b);
  return(INIT_SUCCEEDED);
  }

void OnTick(){}

Thanks 

[William Roeder]

1. Lorentzos Roussos: Is there a way method A would work ?
   

   Add a #define CCanvas . either in the include or just after the #include.

   #include <Canvas\Canvas.mqh>
   #define CCanvas .
   //A :
   #ifdef CCanvas
       string message_from_a="CANVAS IS INCLUDED";
   #else
       string message_from_a="CANVAS SHOULD BE INCLUDED";
   #endif

2. Lorentzos Roussos: (to include a library if its not included already if it is required)

   Just include it if you use something from it.
   

[Lorentzos Roussos]

William Roeder:

1. Add a #define CCanvas . either in the include or just after the #include.
2. Just include it if you use something from it.
   

Thanks