Boost Shared Pointer array

Question

I am new to boost and I came across the boost pointer.

float *value = new float[9]; 
value[0] = 5; ...

The above is my initial c++ code.

I converted the above to boost shared pointer

boost::shared_ptr<float> value (new float);

But when I try to add to value it gives me error that i cant use operator[].

I guess this is too basic, but can I get some info on how to add values to memory pointed by the boost pointer.

Boost ugly? It's one of the most respected C++ libraries there is. Many things from Boost find their way into the standard (e.g. shared_ptr) such is the level of authority is has on the C++ community. The Spirit EBNF grammar parsing library is simply brilliant. — Bathsheba
– Bathsheba, Commented Apr 23, 2015 at 11:02
This is bad for two reasons. C++ now has a standard shared point, std::shared_ptr so you should use that rather than boosts offering. Further, unless you have a significant reason otherwise, you should std::vector or std::array for 'array like' things. — thecoshman
– thecoshman, Commented Apr 23, 2015 at 11:02
@Bathsheba: That's an appeal to authority. Boost has just as much crap as anywhere else- sometimes more. And finding your way into the Standard is no mark of quality- see std::async, std::future, std::thread, std::vector<bool>, u8 literals, and so many more. — Puppy
– Puppy, Commented Apr 23, 2015 at 11:32

Bathsheba · Accepted Answer · 2015-04-23 10:52:55Z

3

boost::shared_ptr<> is not designed to be used to hold an array that's "decayed" to a pointer.

For starters, it wouldn't delete the memory correctly on destruction (it would call delete rather than delete[].) You'd have to build your own deallocator to circumvent this. Possible but tedious.

Keep things simple: use std::vector<float>. In the current standard, the underlying data are guaranteed to be contiguous, and data() can be used to extract the underlying array.

answered Apr 23, 2015 at 10:52

Bathsheba

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kcc__ Over a year ago

Thanks I finally understand why I was getting an error message. Besides that as you mentioned std::vector<>. If I use instead just float value[9] = {} to allocate memory do you think it is good.

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