INV_PTHREAD_ID
item->last_reader_id = item->writer_id = INV_PTHREAD_ID;
item->last_reader_id = INV_PTHREAD_ID;
if (rr->id == id || rr->id == INV_PTHREAD_ID)
rw->writer.id = INV_PTHREAD_ID;
rr->id = INV_PTHREAD_ID;
rw->writer.id = rw->reader.id = INV_PTHREAD_ID;
if (rr->id == INV_PTHREAD_ID) {
0, {INV_PTHREAD_ID, 0, 0, 0}, \
0, 0, {INV_PTHREAD_ID, 0, 0, 0}}
0, {INV_PTHREAD_ID, 0, 0, 0}, \
0, 0, {INV_PTHREAD_ID, 0, 0, 0}}
pthread_t var ## _owner = INV_PTHREAD_ID
var ## _owner = INV_PTHREAD_ID; \