linker issue with freeRTOS osMailQId

[MK..1]

Hi

In main.c I have got these lines:

 osMailQDef (object_pool_q, 10, MEM_memberTypeDef); // Declare mail queue

 osMailQId (object_pool_q_id);

 object_pool_q_id = osMailCreate(osMailQ(object_pool_q), NULL);

in another file in my therad I want to access object_pool_q_id,

extern osMailQId (object_pool_q_id);

extern osMailQId (object_pool_q_id);

void Start_Mem_Task(void const * argument)

{

 while (1) {

osEvent event = osMailGet(object_pool_q_id , osWaitForever);

...

}

}

The linked complains:

undefined reference to `object_pool_q_id'

What is going wrong?

Thx