Question

We open a boost shared memory that was created by another process like this

  boost::interprocess::managed_shared_memory segment(boost::interprocess::open_only, "SharedMem");

But if the process that created the shared memory was a root user, then the process reading it, if it was a normal user, will fail with the reason as:

terminate called after throwing an instance of 'boost::interprocess::interprocess_exception'
what():  Permission denied

What should i do to avoid this? that is to give permission to the shared memory to all?

Answer 1

If you look at the shared_memory constructor, it takes a permissions object. boost::interprocess::permissions::set_unrestricted is probably what you are looking for

void set_unrestricted();
//Sets permissions to unrestricted access:
//        A null DACL for windows or 0666 for UNIX.

According to this, it was added in 1.45 version