I&#39;m trying to wrap my head around how I would implement a vector of unions of strings/integers/doubles in shared memory. (for those familiar with Micro$oft COM, this would essentially be a SAFEARRAY of VARIANTs)<br><br>
I got a quick example of shared memory working &amp; seem to have a decent handle on the basics. I guess there are two things that I&#39;m not quite confident in:<br><br>(1) how to make a containable element work nicely within shared memory, e.g. if I have a structure S that needs to allocate shared memory dynamically during its lifetime (and automatically deallocate upon destruction), how do I store the allocator? (or do I?) If I allocate the memory myself and store it in an offset_ptr&lt;&gt;, I can do that, but I need it to manage the shared memory itself. In particular, one process may need to construct some anonymous object X within the shared memory segment and store the result in an offset_ptr&lt;&gt;, and another process may be the one destroying the memory of X later on.<br>
(2) unions or Boost.Variant that would work with shared memory-- gack!<br><br>I am looking for insight both into the general case (all elements of the vector are polymorphic, vector size can vary) and the following specific case: I have a fixed-size vector, format &quot;defined&quot; at runtime using an array of enums that designate the type of variable that can be stored in each element of the vector. If it weren&#39;t for string support, I would just allocate a fixed-size chunk of memory rather than a vector, and do all the management within the chunk myself by calculating element size + offsets + what have you, which I&#39;ve done before in other contexts. I can still do that if I can store a handle to the string (e.g. an offset into the shared memory segment?) rather than a pointer or other high-level object, so that my &quot;vector&quot; object becomes a class that just has to know how to allocate/deallocate memory on its own (hence question #1 still needs an answer, but I can avoid question #2).<br>
<br>p.s. there seems to be a lot of missing methods in the documentation for shared_memory_object and managed_shared_memory (e.g. allocate(), construct(), destroy(), destroy_ptr()). Or am I missing something?<br><a href="http://www.boost.org/doc/libs/1_35_0/doc/html/boost/interprocess/shared_memory_object.html">http://www.boost.org/doc/libs/1_35_0/doc/html/boost/interprocess/shared_memory_object.html</a><br>
<a href="http://www.boost.org/doc/libs/1_35_0/doc/html/boost/interprocess/basic_managed_shared_memory.html">http://www.boost.org/doc/libs/1_35_0/doc/html/boost/interprocess/basic_managed_shared_memory.html</a><br>