IKillSwitch

IKillSwitch defines the interface for components that enforce emergency shutdown conditions in the trading system, typically in response to loss limits, excessive order flow, or abnormal conditions.

class IKillSwitch : public ISubsystem {
public:
  virtual ~IKillSwitch() = default;

  virtual void check(const Order& order) = 0;
  virtual void trigger(const std::string& reason) = 0;
  virtual bool isTriggered() const = 0;
  virtual std::string reason() const = 0;
};

Purpose

• Provide runtime protection against runaway strategies, loss accumulation, or systemic failures by halting all trading activity.

Responsibilities

Method	Description
check(order)	Evaluates the incoming order against risk limits.
trigger()	Manually activates the kill switch with a reason string.
isTriggered()	Returns whether the kill switch is currently active.
reason()	Returns the human-readable cause of activation.

Notes

• Implements ISubsystem, allowing coordinated startup and reset across engine lifecycle.
• Can be wired into strategy layer, order executor, or global event loop.
• Once triggered, downstream components are expected to halt order submission and processing.