ocs_vsnprintf
ocs_vsnprintf(valuebuf, sizeof(valuebuf), fmt, ap);
ocs_vsnprintf(lock->name, MAX_LOCK_DESC_LEN, name, ap);
ocs_vsnprintf(sem->name, sizeof(sem->name), name, ap);
written = ocs_vsnprintf(segment->buffer + segment->buffer_written, avail, fmt, ap);
written = ocs_vsnprintf(segment->buffer + segment->buffer_written, avail, fmt, save_ap);