extendable mremap on anonymously mmaped memory

I was believing mremap would have a realloc-like behavior until debugging things like the following lines of cod开发者_如何学Ce in C.

#define PAGESIZE 0x1000
void *p = mmap(0, PAGESIZE, PROT_READ | PROT_WRITE | PROT_EXEC, MAP_ANONYMOUS | MAP_SHARED, -1, 0);
void *p2 = mremap(p, PAGESIZE, PAGESIZE * 2, MREMAP_MAYMOVE);
// then any future access to the 2nd page in p2 would generate a nice SIGBUS

After viewing several old threads in some mailing-lists I know mmap was originally designed for 'pure' file mapping and folks who designed mremap seem not caring about codes like that above.

I know a shared memory object would do for this. But shm_open/shm_unlink require filenames and I don't want to deal with strings in this very project. And, I am not sure, maybe shared memory objects would more or less reduce performance of my application.

I'm just wondering if it's possible to make mremap work fine(fine here means no SIGBUS when expanding) with anonymously mapped memory, or if there is some similar methods simple&fast?

thx to all in advance :-)