CODEWITHSUNDEEP
c++boostshared-memoryboost-interprocess
user997112
user997112

Reputation: 30645

Boost Interprocess managed_shared_memory size parameter value?

I'm using Boost Interprocess to map a vector in shared memory.

This is the code I have from Boost tutorials:

using namespace boost::interprocess;
using ShmemAllocator = allocator<int, managed_shared_memory::segment_manager>;
using MyVector = boost::interprocess::vector<int, ShmemAllocator> MyVector;

//                                                    question refers to this size
//                                                                V
managed_shared_memory segment(open_or_create, "MySharedMemory", 65536); 

const ShmemAllocator alloc_inst (segment.get_segment_manager());

MyVector *myvector = segment.construct<MyVector>("MyVector")(alloc_inst);
myvector->resize(SIZE);

I resize my vector after creating the managed_shared_memory.

However, what happens if the managed_shared_memory size argument is smaller than the vector memory allocation?

Rewording the question: how do I choose a size for the managed_shared_memory?

Upvotes: 1

Views: 945

Answers (1)

sehe
sehe

Reputation: 393769

However, what happens if the managed_shared_memory size argument is smaller than the vector memory allocation?

Have you tried? Live Demo:

terminate called after throwing an instance of 'boost::container::length_error'
  what():  get_next_capacity, allocator's max size reached

Rewording the question: how do I choose a size for the managed_shared_memory?

Carefully. Seriously, see e.g.:

Also, segments can be resized/grown, and I have multiple answers on that ranging from simple to advanced: https://stackoverflow.com/search?tab=newest&q=user%3a85371%20interprocess%20grow

Upvotes: 1

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