COW-Mach.cpp

#include <stdio.h>
#include <mach/mach.h>
#include <mach/mach_vm.h>

static const size_t LENGTH = 10;
static const size_t SIZE = sizeof(int) * LENGTH;

void fillBuffer(int* buffer, size_t length)
{
    for (size_t i = 0; i < length; ++i)
		buffer[i] = i;
}

#define PRINT_BUFFER(buffer, length) \
	printf(#buffer " = { "); \
	printBuffer(buffer, length); \
	printf(" }\n");

void printBuffer(int* buffer, size_t length)
{
	if (length) {
		printf("%d", buffer[0]);
		for (size_t i = 1; i < length; ++i)
			printf(", %d", buffer[i]);
	}
}

int main()
{
	int* a = 0;
	mach_vm_allocate(mach_task_self(), (mach_vm_address_t*)&a, SIZE, VM_FLAGS_ANYWHERE);

	fillBuffer(a, LENGTH);

	mach_port_t handle = 0;
	vm_size_t size = vm_page_size;
	mach_make_memory_entry(mach_task_self(), &size, (mach_vm_address_t)a, VM_PROT_READ | VM_PROT_WRITE, &handle, 0);

	int* b = 0;
	mach_vm_map(mach_task_self(), (mach_vm_address_t*)&b, vm_page_size, 0, TRUE, handle,  0, TRUE, VM_PROT_READ | VM_PROT_WRITE, VM_PROT_READ | VM_PROT_WRITE, VM_INHERIT_DEFAULT);

	fillBuffer(a + 1, LENGTH - 1);

	printf("a = %p\n", a);
	printf("b = %p\n", b);
	PRINT_BUFFER(a, LENGTH);
	PRINT_BUFFER(b, LENGTH);
	return 0;
}