Can I malloc a space larger than 3G bytes?

[warrener]

We know that a process memory space is limited by 4G (1G for kernel).
I am thinking if I can malloc a space larger than 3G. So I tried the following:

int main()
{
	char* x = (char*)malloc(3*1024*1024*1024);
	return 0;
}

AND It works! ....
Anybody knows why?

I also tried

char x[0x7fffffff];

This time compiler complains for its size. So I guess the implementations of malloc and char[] are different, right?