Bug in MetaTrader

[PipCop]

This was sent to me yesterday, just a heads up:

Dear all,

i got a heads up from a respected trader informing that a MT4 broker has discovered a bug in MT4. it intermittently affects OrderClose and EA-side (in-code) trailing stops, potentially leaving positions open when they should be closed.

more details below.

ck

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To all ATC EA traders,

Please be aware that ATC has discovered a known bug in the MT4, causing intermittent operation of EAs. Further, due to the nature of how this bug affects EA operation, it affects the server flow control that the AR system relies on to provide stable operation to EA’s. For reasons beyond the scope of this notice, we do not believe that Metaquotes is inclined to solve this problem right away, given we have notified them. Therefore it is ATC’s place to be sure that our traders are aware of the issue and until we have solved the problem here, (hopefully by this weekend), traders can decide from the information below, if they should continue trading today.

Cause: The AR kit ATC is developing, uses most of the available server flow control commands that MQ provides for “Controlled and Proper” server communication, which in part plays a role in connection stability and CPU / TCP control. It further assures against poorly written EAs / scripts from “storming” the server in an uncontrolled manner. Since the MT bug is directly involved in one of the critical flow control commands, the more a programmer relies on better flow control coding, the more likely the problem will interfere with an EA; clearly a “Catch 22” which speaks to a long history of problems with MT4.

This problem affects all MT brokers, not just ATC. Sadly, many brokers do not impose proper EA design and therefore it may falsely “appear” some are not affected.

Impact: Traders may find that EA’s which do perform orderly flow control, may suddenly refuse to trade, without warning. If logging is turned on and the experts tab reads “Not Connected” or “IsConnected = False“, during failure to trade, then the bug in MT has surfaced, which can be proven by verifying that ticks are still flowing into the price feed, while the EA is failing in this way. Normally, this results simply in an EA that cannot “create” a trade. HOWEVER, if the bug surfaces while trades are in play AND the EA in question directly manages CloseOrder events, the EA may fail to close the order timely and the price then can pass through the intended close. This is mostly an exposure where the EA itself is managing a direct “OrderClose” or the trailing of a TP or SL is being done in code. Fortunately this affects less EAs as these forms of order close are not commonly used by most EA designers.

It is also possible, depending on the EA design, that a standard “Trailing Stop” fired from within the EA, could also fail to fire and therefore the trailing stop may not advance as it would normally, had it been fired manually from the MT4 by the user and the result would be higher losses or a failure to capture profit via trailing stop.

Fortunately, discovery of this problem comes at End of Year when most traders tend to lay back and wait for volume to pick up in coming days. Accordingly, ATC programmers are now working around the clock, through the weekend to develop a solution we feel will remove this exposure completely, regardless of Metaquotes apparent dismissal of the issue.

If a trader is uncertain if his EA could be affected this way, ATC recommends holding up on trading for today and until a solution is announced this weekend.

We do expect the solution will be two fold…

1) An AR update at revision 0.032, by this Sunday evening which will include a DLL requirement and enable safe trading immediately

2) The eventual replacement of the OpenSource OrderReliable include file, for a closed source retail replacement, scheduled for January 15, to complete.
Thank you for your attention to this issue and please watch for further news as we complete testing.

ATC Brokers - Support