...
On failure, this function returns an error code in the format described in Return codes.
Remarks
If there are no HostIDs of the requested type, the string will be empty. If there is more than one of the requested type, the HostIDs are separated by commas.
...
ETHERNET=0123456789012345,ETHERNET=54321009876543210,..."
To make use of custom HostIDs, you must set a callback function using LMX_SetOption with the flag LMX_OPT_CUSTOM_HOSTID_FUNCTION.