How to reduce the TP in an open position?

[Josh Pilisuk]

I want to lower the TP of my first opened position by 10 pips,  how would you do this?

#include <Trade\Trade.mqh>
CTrade trade;

void lowerTargetProfitOfOldestPosition() {
   if(PositionsTotal() == 0) {
      return;
   }
   
   int ticket = PositionGetTicket(0);
   double priceTP = PositionGetDouble(POSITION_TP);
   double newTP = priceTP-0.001;
   trade.PositionModify(ticket,0,newTP);
}

[Vladimir Karputov]

Josh Pilisuk :

I want to lower the TP of my first opened position by 10 pips,  how would you do this?

The "first" position is the position with the shortest opening time. You started using Ctrade - that's good. You need to go ahead and use CPositionInfo.

//+------------------------------------------------------------------+
//|                                                            1.mq5 |
//|                        Copyright 2020, MetaQuotes Software Corp. |
//|                                             https://www.mql5.com |
//+------------------------------------------------------------------+
#property copyright "Copyright 2020, MetaQuotes Software Corp."
#property link      "https://www.mql5.com"
#property version   "1.00"
//---
#include <Trade\PositionInfo.mqh>
#include <Trade\Trade.mqh>
//---
CPositionInfo  m_position;                   // object of CPositionInfo class
CTrade         m_trade;                      // object of CTrade class
//+------------------------------------------------------------------+
//| Script program start function                                    |
//+------------------------------------------------------------------+
void OnStart()
  {
//---
   m_trade.SetExpertMagicNumber(300);
   m_trade.SetMarginMode();
   m_trade.SetTypeFillingBySymbol(Symbol());
   m_trade.SetDeviationInPoints(10);
//---
   datetime time=D'2500.01.01 00:00';
   ulong ticket=0;
   for(int i=PositionsTotal()-1; i>=0; i--) // returns the number of current positions
      if(m_position.SelectByIndex(i)) // selects the position by index for further access to its properties
        {
         if(m_position.Time()<time)
           {
            time=m_position.Time();
            ticket=m_position.Ticket();
           }
        }
//---
   if(time!=D'2500.01.01 00:00')
     {
      m_trade.PositionModify(ticket,...);
     }
//---
  }
//+------------------------------------------------------------------+