Thread questions

Hi,

I have a thread question.

Give an example:
resource_A <--> mutex_A
resource_B <--> mutex_B

I need do copy from resource A to resource B, so I do like following:

pthread_mutex_lock(mutex_B)
pthread_mutex_lock(mutex_A)
memcpy(resource_B, resource_A, sizeof(resource_A));
pthread_mutex_unlock(mutex_A)
/* Q: Can other thread do operation on resource_A now or after the following
unlock??? */

pthread_mutex_unlock(mutex_B)

Thanks,
Eric