Boost C++ Libraries: Ticket #12207: allocate_shared using fast_pool_allocator results in member vector iterator memory corruption on MSVC

Boost C++ Libraries: Ticket #12207: allocate_shared using fast_pool_allocator results in member vector iterator memory corruption on MSVC https://svn.boost.org/trac10/ticket/12207 Reproducer: <pre class="wiki">#include <vector> #include <boost/pool/pool_alloc.hpp> struct TestStruct { std::vector<int> vec; }; int main() { //std::allocator<TestStruct> allocator; // works boost::fast_pool_allocator<TestStruct> allocator; auto test = std::allocate_shared<TestStruct>(allocator); test->vec.push_back(1); auto iter = test->vec.begin(); auto val = *iter; } </pre> When dereferencing iter it will assert "vector iterator not dereferencable" on MSVC (using 2015 Community Edition) everytime on 64-bit and sporadically on 32-bit. If you put a break point (or break after the assert) and check <pre class="wiki">"iter" -> "[Raw View]" -> "std::_Vector_const_iterator ..." -> "std::_Iterator012 ..." -> "std::_Iterator_base12" -> "_Myproxy" -> "_Mycont" -> "_Myproxy" </pre> you can see that the _Myproxy of _Mycont is "0xcccccccccccccccc" (uninitialized) when it should point to the _Myproxy of std::_Iterator_base12, forming a loop (which is the case when using std::allocator for the allocation). Note that the times it works when you compile on 32-bit the memory still seems to be corrupted (it's just not set to "0xcccccccccccccccc"). en-us Boost C++ Libraries /htdocs/site/boost.png https://svn.boost.org/trac10/ticket/12207 Trac 1.4.3