This is how a halt affects orders as I understand it. That is to say, it won't affect a pre-existing order at all unless you cancel it yourself.

Here's a link to the information I found. Page 44

http://apps.tmx.com/en/pdf/TMX-Order-Types-Guide.pdf

"6.2.1 Halts

Halts are manually applied and lifted by Trading Services, and notification messages are sent out on all public market data feeds. Securities may be halted or lifted at any time during the trading day, from the Pre-Open until the end of the Extended Trading session. Alpha has two types of halts that can be applied to securities: No Matching halt and Full halt.

No Matching Halt

The majority of halts are “No Matching” Halts, and are imposed by Regulators pending news regarding the issuer of the security. During a No Matching halt, order entry and amendment is allowed, as well as cancels, but there is no matching. When in No Matching halt state, the security behaves as in the Pre-Open Trading session, where the book can be crossed and the indicative auction price is continually calculated based on order activity in the book. A Calculated Opening Price (COP) is broadcasted while the stock is in halt state. When the halt is lifted, an auction similar to the Market Opening takes place, and continuous trading resumes. For examples, please see the Opening Allocation section.

Full Halt

In a full halt, order entry, order amendment and order matching is suspended, however orders may be cancelled."

The 'Document Management' section near the beginning says this document must be updated annually but this one appears to be current even though it's dated copyright 2013.

I've heard the same on this board before regarding all orders being cleared in the event of a halt. This is what I've found on the subject and it doesn't seem to support that. Feel free to shed some light on the subject if anyone has evidence to support a different view. :)

Green