Common EA library for multi instances

You could call me a multitasker. At this moment I trade manually at 2 MT4 instances. And I am developing on 3 experts, using 3 more instances. I have worked this way for years.

I found that it is best to have all experts developed from the same instance. Otherwise you lose track over time about where the development of an expert is located, because you keep moving the MQ4 files around. But then I have to develope in one MT4 instance and move the .EX4 file to another instance to have it running in a forward test. For every small change I have to do that.

My question is: Can I have all EA's placed in a common directory - maybe placed in a folder on the Desktop, and tell the different instances of the MT4 to link to taht folder when installling experts?

So now I have moved about 10 robots to a directory on the Desktop. That was such a nice feeling to have everything gathered in one place. Nice and orderly and easy to find the stuff. I started to work on a robot. Of cause using MetaEditor like I allways does. But it doesn't work!!! The robot compiles nicely and I moved it to a MT4 instance, but got thi message when trying to install it - tried with another robot also,with the same result. Does anybody have a clue on how to have one directory servicing multiple instances of MT4????

Just use the MQL5 storage facility. You can load any EA to any instance of MT4 by using MQL5 community ID

That is very usefull. I have never heard of it, since I don't concentrate on MT5. Will investigate it now. Thank you very much.

Hmm - maybe it's time to try out a MT5 account.

Hi RiskFighter,

I have a Development instance of MT4 and 3 Live Instances across 3 PC's (Each PC has 2 instances of MT4). I use Vanilla MT4 | Forex Factory and a concept by emmzett here: Vanilla MT4 | Page 2 | Forex Factory, using Link Shell Extension (schinagl.priv.at) and Symbolic Links.

On my Development PC I have 2 instances of MT4, Dev and Live, when I am happy with my coding I copy the EX4 to the Live instance. I use Symbolic Links from my Development PC's Live instance to the Live MT4 instances on the other PC's, in effect replicating 1 Live instance of MT4 to 2 other MT4 instances.

Another option for you to explore.

TimeFX

Actually you don't need MT5. The MQL storage facility works fine with the MQL4 meta editor.

I already posted this elsewhere on ForexFactory but I forget where. So here we go again...

(1) You set up one single MQL project where all your files (indicators, experts, libraries, include files) exist only once. This setup is outside of any MetaTrader installation, let's say on "D:\my-projects\mql". This MQL directory is your development directory. You put it under version control (whatever VCS you prefer except MQL Storage - never use that one).

(2) You install as many MetaTrader instances in whatever directory you like. I have all my 20 instances in one directory "E:\Trading\MetaTrader" but you can put every single one wherever you like. They can be in different locations anywhere on your computer, even on USB sticks or network drives.

(3) You install the freeware Link Shell Extension by Hermann Schinagl. It manages softlinks and hardlinks under Windows as if you are on Linux. With this you can create virtual directories pointing to another location on your harddrive. To Windows it looks like a regular file or directory. Practically you are able to mirror a directory tree in another directory. This software integrates with Windows File Explorer and after installation you have for every directory or file additional menu entries in the File Explorer's context menu, which allows you to create virtual links to the selected file/directory (I tried to express this in layman terms as good as I could).

(4) You go into every MetaTrader data directory and delete the "MQL4" folder. Instead you put there a softlink or a junction to your project directory (your MQL development directory). You do this for every single MetaTrader instance you have. Read the documentation of the LinkShell extension to understand what I just wrote.

(5) Now everytime you change something in your development directory that change is automatically mirrored and visible to all your MetaTrader setups. You only need to write code once, and compile your sources once. There are tricks to refresh each MetaTrader instance automatically but for a start I recommend to open MetaTrader's "Navigator" window and click "Refresh" manually.

Attached is a screenshot how the directory structure of this setup may look like. I use Eclipse and UEStudio as development environment (you use whatever you prefer) and Git as VCS (again your choice can be different) together with 20 MetaTrader instances. My MQL project is hosted publicly on Github (see the link in my profile). This project is not only synchronized to the local MT4 instances but also to two VPS at the internet where experts/indicators/scripts are running 24/7.


I assume there will be a lot of questions. So look-up the tools and get comfortable with them, and then ask. Please get familiar with the tools first.

ps: A big thank you to @timefx for posting the link to my previous answer.

I am using same approach for developing EA but have to refresh manually. Would you shed some lights on how to do it automatically?
Can EA auto refreshed on VPS too after deployed or only for local MT4s ?