Sleep() function wrongly documented in the mql4 reference

I would imagine that MT4's Sleep() function is a simple wrapper around the Win32 Sleep() function. That's got well-known limitations as e.g. summarised in the 4th post on the following page:

http://social.msdn.microsoft.com/Forums/en-US/csharpgeneral/thread/ffad3056-6913-4a09-b2f9-5ceb1a67a06a

Personally, I don't think it's unreasonable for MetaQuotes to omit these detailed caveats from their documentation. They could perhaps add something like the following: "Only use Sleep() for short-term delays to stop your EA consuming 100% of processor time. Do not use it in order to delay execution for a precise, lengthy period of time."

MQL4 is a russian software...not a swiss one :)

You can't go changing the time base of your computer and expect the timers to run at the same speed. It's like changing the length of the pendulum of a grandfather clock from 1 metre to 2 metres and expect it to still tick in seconds or like fitting big wheels to your car and expecting the speedo to read the right speeds. The most annoying thing is Sleep() doesn't work in an indicator.

The most annoying thing is Sleep() doesn't work in an indicator.

I have write this code which is compatible with backtester. May be is't ok with indicator. I let you try.

#import  "shell32.dll"   
#import "kernel32.dll"

int SleepEx( int dwMilliseconds, bool bAlertable);    


#include <WinUser32.mqh>
#include <stderror.mqh>
                                                    

// Sleep compatible avec le tester
//------------------------------------------------------------------------------------------------------------------------------------- Waiting
void Waiting(double MesSecondes=0)
{
   if (IsTesting() || IsOptimization())
   {
   int Tempo = (1000 * MesSecondes);
   
   SleepEx(Tempo,false);         
   }
   else
   {
   Sleep(MesSecondes*1000);            //sleep libère le processeur pour autre tâche mais n'est pas reconnu par le tester
   }
}
//------------------------------------------------------------------------------------------------------------------------------------- 

Thanks for the code but why would you want the sleep command to work in back testing mode? Time does not run as real time in the back tester so why would you want to wait a real number of seconds? I don't understand. If a psuedo delay is required in the code during back testing then surely it must take a note of the tick time and decide if the next tick is at a greater time than the required delay. It certainly can't be acccurate because there is no clock during back testing only tick times.

Only for cpu management while waiting for file be copied or created by other program call from my ea

You don't need the wait. Display the current values, once the file is updated, display the updated values on the next tick. If you're depending on an asynchronous task to update, then the indicator should change asynchronously.

In visual mode backtesting it is usefull.