>>>>> "Niko" == Niko Matsakis <niko@xxxxxxxxxxxx> writes:
>> What is the current correct approach to instantiating objects
>> in shared memory so that multiple processes can access the C++
>> objects?
Niko> I don't know the answer to your question. However, I am
Niko> wondering, are your two processes executing the same
Niko> executable?
Niko> I'm sure you're assumption is correct: the C++ object
Niko> contains pointers to its virtual table (if it has virtual
Niko> functions).
Niko> My guess is that if you running the same executable, and
Niko> you're having problems, then the virtual dispatch tables are
Niko> dynamically allocated and you're screwed unless there is
Niko> some magic g++ option I don't know about.
My goal is to run separate executables which both access objects in
shared memory. Stroustrup's 3rd Edition implies that shared memory
allocators for C++ are possible in Sect. 19.4. I have had this type
of mechanism running with earlier gcc/g++ versions. I am still not
sure that I am not simply making some type of mistake in my
application.
Niko> However, you could also work around this by using function
Niko> pointers stored in the class instances (if you are using the
Niko> same executable in which case I *think* the functions would
Niko> be loaded at the same spots in the two processes memory
Niko> space), or, more robustly, indexes into a table of function
Niko> pointers shared by the two processes.
I am working toward an upgrade of a shared memory allocator for the
STL.
Thanks for your suggestions,
Marc
--
Marc Ronell, PhD CSE, PE EE
