How to Initialize array of pointers in a c++ Initializer List

Question

My class has an array of pointers (Code edited for illustrating point)

class IMX6S::IMX6SAnalogIn : public AP_HAL::AnalogIn {
public:
    IMX6SAnalogIn();

private:
    IMX6S::IMX6SAnalogSource* _channels[2];
};

class IMX6S::IMX6SAnalogSource : public AP_HAL::AnalogSource {
public:
    friend class IMX6S::IMX6SAnalogIn;
    IMX6SAnalogSource(int16_t pin, float initial_value);


};

I want to initialize the _channels array in the initializer list of the constructor so I attempt the following

IMX6SAnalogIn::IMX6SAnalogIn() :
     _channels{&IMX6SAnalogSource(0,0.0f),&IMX6SAnalogSource(1,0.0f) }
{
}

However I get a warning - Taking address of temporary. in the initializer list

Is this way of initializing the array in the initializer list incorrect?

Note - I cannot dynamically allocate memory. Everything has to be statically allocated.

You wouldn't get a warning if it were correct.

Rob K
– Rob K

2015-12-01 20:49:08 +00:00
Commented Dec 1, 2015 at 20:49 — Rob K
– Rob K, Commented Dec 1, 2015 at 20:49
please use smart pointer

Bryan Chen
– Bryan Chen

2015-12-01 20:49:43 +00:00
Commented Dec 1, 2015 at 20:49 — Bryan Chen
– Bryan Chen, Commented Dec 1, 2015 at 20:49

Nicol Bolas · Accepted Answer · 2015-12-01 23:09:50Z

2

You can stop making it an array of pointers and make it an array of objects:

std::array<IMX6S::IMX6SAnalogSource, 2> _channels;

IMX6SAnalogIn::IMX6SAnalogIn() :
     _channels{{0,0.0f},{1,0.0f}}
{
}

There is no way to do this with an array of pointers without allocating memory. Well, you could make the objects direct members of the class and store pointers to them in an array that's also a member of the class. But that's functionally no different than the above.

edited Dec 1, 2015 at 23:09

answered Dec 1, 2015 at 20:55

Nicol Bolas

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