Gets GID, which is the NIC's MAC address.
Syntax
#include <rdma/verbs.h>
int ibv_query_gid(struct ibv_context *context, uint8_t port_num, int index, union ibv_gid *gid)
Description
The ibv_query_gid() routine
returns the NIC's MAC address in subnet_prefix and 0 in the interface_id.
Input Parameters
| context | Specifies the context pointer returned by ibv_open_device(). | 
| port_num | Specifies port number for the device returned
by ibv_query_device(). | 
| index | Specifies index for port_num deduced from attributes
returned by ibv_query_port(). | 
Output Parameter
| gid | Specifies the pointer to store GID. | 
Return Values
| 0 | On success. | 
| -1 | If the request fails because, the context or gid parameter
is NULL or the open or write operation failed on the OFED admin device /dev/rdma/ofed_adm. | 
ibv_gid
union ibv_gid 
{ 
       uint8_t      raw[16]; 
       struct 
       { 
           uint64_t subnet_prefix; 
           uint64_t interface_id; 
       } global; 
};