IGameInputDevice::GetForceFeedbackMotorInfo

uint32_t GetForceFeedbackMotorInfo(
    uint32_t infoArrayCount,
    GameInputForceFeedbackMotorInfo* infoArray
);

uint32_t motorCount = device->GetForceFeedbackMotorCount();
std::vector<GameInputForceFeedbackMotorInfo> motorInfo(motorCount);
motorInfo.resize(device->GetForceFeedbackMotorInfo(motorCount, motorInfo.data()));

for (uint32_t motorIndex = 0; motorIndex < motorInfo.size(); ++motorIndex)
{
    if (motorInfo[motorIndex].isConstantEffectSupported)
    {
        GameInputForceFeedbackParams params = {};
        params.kind = GameInputForceFeedbackConstant;
        // Fill in the remaining effect parameters...

        Microsoft::WRL::ComPtr<IGameInputForceFeedbackEffect> effect;
        device->CreateForceFeedbackEffect(motorIndex, &params, &effect);
    }
}