Can I resize Linux shared memory with shmctl?

Question

I have a C++ application that allocates shared memory on a Linux system via shmget(2). The data that I store in the shared memory grows periodically, and I\'d like to resize th

Answer 1

It seems for me that you can write your own memory manager for your purpose. The conception is quite simple:

1. You have a shared memory block which size is N bytes;
2. Allocate new block of shared memory with 2*N size;
3. Copy memory from one block to another;
4. Free the old shared memory block;
5. Wrap the #2-4 into some routine and use it;

I'm afraid we have nothing more to do with that. This is how std::vector is implemented. And void *realloc() in most of cases will return you the pointer to the new block of memory (but not to the extended old block).