[ns] node position returns all the time zero

[Ghofrane]

Hi 
I want to know the current position of a node, but when I write this: 
node_ = (MobileNode*)Node::get_node_by_address(ra_addr());
((MobileNode *)Node::get_node_by_address(ra_addr()))->getLoc(&x, &y,&z); 

tcl.evalf("puts \" (sendHello) x position is  %d  :\"",x);

It returns all the time 0 !
Do you have any suggestion to solve this problem ?
Thank you.