Règle correspondante
Canada
Practice Relating to Rule 15. The Principle of Precautions in Attack
Section C. Feasibility of precautions in attack
Canada’s LOAC Manual (1999), with respect to the standard of care to be applied to target verification, precautions in the choice of means and methods of attack and the assessment of the effects of an attack, states:
Commanders, planners and staff officers will not be held to a standard of perfection in reaching their decisions.
Commanders, planners and staff officers are required to take all “feasible” steps to verify that potential targets are legitimate targets. However, such decisions will be based on the “circumstances ruling at the time”. Consideration must be paid to the honest judgement of responsible commanders, based on the information reasonably available to them at the relevant time, taking fully into account the urgent and difficult circumstances under which such judgements are usually made.
The test for determining whether the required standard of care has been met is an objective one: Did the commander, planner or staff officer do what a reasonable person would have done in the circumstances? 
Canada, The Law of Armed Conflict at the Operational and Tactical Level, Office of the Judge Advocate General, 1999, pp. 4-3/4-4, §§ 25–27.
Canada’s LOAC Manual (2001) states in its chapter on targeting:
418. Standard of care
1. Commanders, planners and staff officers will not be held to a standard of perfection in reaching their decisions.
2. Commanders, planners and staff officers are required to take all “feasible” steps to verify that potential targets are legitimate targets. However, such decisions will be based on the “circumstances ruling at the time”. Consideration must be paid to the honest judgement of responsible commanders, based on the information reasonably available to them at the relevant time, taking fully into account the urgent and difficult circumstances under which such judgements are usually made.
3. The test for determining whether the required standard of care has been met is an objective one: Did the commander, planner or staff officer do what a reasonable person would have done in the circumstances? 
Canada, The Law of Armed Conflict at the Operational and Tactical Levels, Office of the Judge Advocate General, 13 August 2001, § 418.1–3.
In its glossary, the manual defines “feasible precautions” as “those precautions that are practicable or practically possible taking into account all circumstances ruling at the time including humanitarian and military considerations.” 
Canada, The Law of Armed Conflict at the Operational and Tactical Levels, Office of the Judge Advocate General, 13 August 2001, Glossary, p. GL-6.
Canada’s Use of Force Manual (2008), in a section entitled “Principles and rules governing the use of force that directly relates to the conduct of armed conflict”, states:
Standard of care. “Feasible” is understood as that which is practicable or practicably possible, taking into account all circumstances ruling at the time, including humanitarian and military considerations. Planners and commanders are expected to act reasonably and in good faith. Decisions concerning the use of force shall be reached on the basis of an assessment of the information reasonably available at the relevant time and that such decisions cannot be judged on the basis of information which has subsequently come to light. Reasonable, good faith efforts must be made to gather intelligence and to review the available intelligence. This standard is one of “reasonableness”, not “perfection”. The test for determining whether the required standard of care has been met is an objective one: “Did the commander, planner or staff officer do what a reasonable person would have done in the circumstances?” 
Canada, Use of Force for CF Operations, Canadian Forces Joint Publication, Chief of the Defence Staff, B-GJ-005-501/FP-001, August 2008, § 112.6.
At the CDDH, Canada stated that the word “feasible” when used in the 1977 Additional Protocol I, for example, in Articles 57 and 58, “refers to what is practicable or practically possible, taking into account all circumstances existing at the relevant time, including those circumstances relevant to the success of military operations”. 
Canada, Statement at the CDDH, Official Records, Vol. VI, CDDH/SR.42, 27 May 1977, p. 224.
Upon ratification of the 1977 Additional Protocol I, Canada stated: “The word ‘feasible’ means that which is practicable or practically possible, taking into account all circumstances ruling at the time, including humanitarian and military considerations.” 
Canada, Reservations and statements of understanding made upon ratification of the 1977 Additional Protocol I, 20 November 1990, § 5.