c++ - Is there a better way to do this than writing a wrapper allocator that stores a reference to a stateful allocator object? -

for example:

struct foo {     mypoolalloc<char> pool;     std::vector<int , mypoolalloc<char>> vec_int; // wrapper allocator replace mypoolalloc<> here.     std::vector<std::function<void()> , mypoolalloc<char>> vec_funcs; // wrapper allocator replace mypoolalloc<> here.      foo() : vec_int(pool) , vec_funcs(pool) {}      // want store lambdas captured variables using custom allocator well:     template<typename func>     void emplace_back(const func& func) {         vec_funcs.emplace_back(std::allocator_arg , pool , func);     } }; 

in above code, want allocations (besides pool itself) pull same pool object. best way writing wrapper allocator stores reference actual stateful allocator object? , pass following constructors (example):

: vec_int ((mywrapperalloc<char>(pool))); 

is there cleaner way writing whole wrapper class mypoolalloc<>?

the standard "allocator" concept have been better named "allocatorreference." each object either refers global instance (stateless) or external object (stateful).

either way, allocator instance within allocator-aware container not own memory pool itself. it's proxy. note allocator objects copied rebound , returned value. don't want vector::get_allocator copy whole memory pool.

so, yes, need 2 classes.

1. the "wrapper," "proxy," or "reference" satisfies standard allocator requirements , takes template parameter allocated type.

2. the memory pool has nothing allocator interface know how perform allocations.