Does mremap work with malloc?

Question

Is

void * mremap(void *old_address, size_t old_size , size_t new_size, unsigned long flags);

compatible with malloc()?

GCC (C++) and using Linux.

Thanks.

Answer 1

No, it is not. Apart from the fact that malloc doesn't need to give you an address at a page border (which is what mremap expects), it would be dangerous to mess with memory mappings from malloc without malloc knowing you did it. Use realloc instead.

Answer 2

No, but it's highly likely it would work if your previously malloced memory was page-aligned. Of course malloc-related calls will get cranky later when they discover you've moved their data. Results could include heap invalidation, data corruption, and segmentation faults.