101 lines
3.6 KiB
MQL5
101 lines
3.6 KiB
MQL5
|
//+------------------------------------------------------------------+
|
||
|
|
//| GlobalsNoCondition.mq5 |
|
||
|
|
//| Copyright 2021, MetaQuotes Ltd. |
|
||
|
|
//| https://www.mql5.com |
|
||
|
|
//+------------------------------------------------------------------+
|
||
|
|
#property service
|
||
|
|
|
||
|
|
#include "..\..\Include\PRTF.mqh"
|
||
|
|
|
||
|
|
// maximal number of concurrently running copies of the program
|
||
|
|
input int limit = 1; // Limit
|
||
|
|
input int startPause = 100; // Delay (ms)
|
||
|
|
|
||
|
|
//+------------------------------------------------------------------+
|
||
|
|
//| Delay emulation |
|
||
|
|
//+------------------------------------------------------------------+
|
||
|
|
void Delay()
|
||
|
|
{
|
||
|
|
if(startPause > 0)
|
||
|
|
{
|
||
|
|
Sleep(startPause);
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
//+------------------------------------------------------------------+
|
||
|
|
//| Service program start function |
|
||
|
|
//+------------------------------------------------------------------+
|
||
|
|
void OnStart()
|
||
|
|
{
|
||
|
|
PrintFormat("\nParameters: Limit: %d, Delay: %d", limit, startPause);
|
||
|
|
// create new temporary variable if it's not exist
|
||
|
|
// keep current value otherwise
|
||
|
|
PRTF(GlobalVariableTemp(__FILE__));
|
||
|
|
|
||
|
|
// precondition guards
|
||
|
|
int count = (int)GlobalVariableGet(__FILE__);
|
||
|
|
if(count < 0)
|
||
|
|
{
|
||
|
|
Print("Negative count detected. Not allowed.");
|
||
|
|
return;
|
||
|
|
}
|
||
|
|
|
||
|
|
if(count >= limit)
|
||
|
|
{
|
||
|
|
PrintFormat("Can't start more than %d copy(s)", limit);
|
||
|
|
return;
|
||
|
|
}
|
||
|
|
|
||
|
|
// emulate slow execution in busy conditions,
|
||
|
|
// where multiple programs run in parallel
|
||
|
|
Delay();
|
||
|
|
// since another instance could have already read the same count
|
||
|
|
// from the gloval varibale and increment it,
|
||
|
|
// out increment operates on outdated value and does not actually
|
||
|
|
// count both instances (we have the same count as other program)
|
||
|
|
PRTF(GlobalVariableSet(__FILE__, count + 1));
|
||
|
|
|
||
|
|
// work cycle (mockup)
|
||
|
|
int loop = 0;
|
||
|
|
while(!IsStopped())
|
||
|
|
{
|
||
|
|
PrintFormat("Copy %d is working [%d]...", count, loop++);
|
||
|
|
// ...
|
||
|
|
Sleep(3000);
|
||
|
|
}
|
||
|
|
|
||
|
|
int last = (int)GlobalVariableGet(__FILE__);
|
||
|
|
if(last > 0)
|
||
|
|
{
|
||
|
|
PrintFormat("Copy %d (out of %d) is stopping", count, last);
|
||
|
|
Delay();
|
||
|
|
PRTF(GlobalVariableSet(__FILE__, last - 1));
|
||
|
|
}
|
||
|
|
else
|
||
|
|
{
|
||
|
|
Print("Count underflow");
|
||
|
|
}
|
||
|
|
}
|
||
|
|
//+------------------------------------------------------------------+
|
||
|
|
/*
|
||
|
|
example output
|
||
|
|
|
||
|
|
GlobalsNoCondition GlobalVariableTemp(GlobalsNoCondition.mq5)=true / ok
|
||
|
|
GlobalsNoCondition 1
|
||
|
|
GlobalsNoCondition 1 GlobalVariableTemp(GlobalsNoCondition.mq5)=false / GLOBALVARIABLE_EXISTS(4502)
|
||
|
|
GlobalsNoCondition GlobalVariableSet(GlobalsNoCondition.mq5,count+1)=2021.08.31 17:47:17 / ok
|
||
|
|
GlobalsNoCondition Copy 0 is working [0]...
|
||
|
|
GlobalsNoCondition 1 GlobalVariableSet(GlobalsNoCondition.mq5,count+1)=2021.08.31 17:47:17 / ok
|
||
|
|
GlobalsNoCondition 1 Copy 0 is working [0]...
|
||
|
|
GlobalsNoCondition Copy 0 is working [1]...
|
||
|
|
GlobalsNoCondition 1 Copy 0 is working [1]...
|
||
|
|
GlobalsNoCondition Copy 0 is working [2]...
|
||
|
|
GlobalsNoCondition 1 Copy 0 is working [2]...
|
||
|
|
GlobalsNoCondition Copy 0 is working [3]...
|
||
|
|
GlobalsNoCondition 1 Copy 0 is working [3]...
|
||
|
|
GlobalsNoCondition Copy 0 (out of 1) is stopping
|
||
|
|
GlobalsNoCondition GlobalVariableSet(GlobalsNoCondition.mq5,last-1)=2021.08.31 17:47:26 / ok
|
||
|
|
GlobalsNoCondition 1 Count underflow
|
||
|
|
*/
|
||
|
|
//+------------------------------------------------------------------+
|