What is the equivalent of Keil _at_ in gcc

Does gcc have any keyword exactly equivalent to _at_ in Keil?

struct Location
{
  uint_32 x;
  uint_32 y;
  uint_32 z;
  char protocol[10];
};

struct link idata list _at_ 0x40;     /* list at idata 0x40 */

Note: I do not want to define a pointer at all. I want an exactly the same variable.

Note: the idata here can be ignored.