Re: Newbie Question Shared Memory Containers/Allocators

From: Ion Gaztañaga (igaztanaga_at_[hidden])
Date: 2020-02-14 04:20:55

On 02/02/2020 7:07, Da Xu via Boost-users wrote:
> Hi everybody,
> 
> how are you?
> 
> I am a completely noob when it comes to Boost.  :D But not a noob when 
> it comes to C++. Though, am a bit noobish when it comes to C++14 and 
> beyond :D
> 
> I am trying to construct a complex data container, which has a vector of 
> floats, on managed shared memory.
> 
> I followed the documentation, added the appropriate headers and made the 
> following declarations:
> 
> typedef managed_windows_shared_memory::segment_manager segment_manager_t;
> typedef allocator<void, segment_manager_t>Â  void_allocator;
> typedef basic_string<char, std::char_traits<char>, char_allocator> 
> shared_string;
> typedef allocator<float, segment_manager_t> float_allocator;
> typedef vector<float, float_allocator> float_vector;
> typedef allocator<float_vector, segment_manager_t> float_vector_allocator;
> 
> class ComplexContainer
> {
> shared_string name;
> float_vector channelData;
> 
> public:
> ComplexContainer(const char * name_, const float* data_start, const 
> float* data_end, const void_allocator& void_alloc) :
>  Â  Â  Â name(name_), channelData(data_start, data_end, void_alloc)
>  Â  Â {}
> 
> ComplexContainer(const void_allocator& void_alloc) :
>  Â  Â name(void_alloc), channelData(void_alloc)
> {}
> 
> 
> ComplexContainer() {}
> 
> 
> }

Hi,

1) shared_string also needs char_allocator as a second parameter.
2) a float vector does not expect a void_allocator, but a 
float_vector_allocator

Best,

Ion