工作程式碼片段-aio

aio是linux上的非同步IO實現，具體測試代碼如下：

    aiocb ab;    bzero( (char *)&ab, sizeof(struct aiocb) );    int fd = open("a.txt", O_RDWR | O_APPEND);    ab.aio_buf = malloc(201);    ab.aio_fildes = fd;    ab.aio_nbytes = 20;    ab.aio_offset = 0;    int r = aio_read(&ab);    std::cout << "return:" << r << std::endl;    std::cout << "buff:" << (char *)ab.aio_buf << std::endl;    r = aio_return(&ab);    std::cout << "return:" << r << std::endl;    char *b = "good boy!!";    ab.aio_buf = b;    aio_write(&ab);

關鍵點在於，struct aiocb結構體的填充。

aio通知機制：

訊號

  ab.aio_sigevent.sigev_notify = SIGEV_SIGNAL;  ab.aio_sigevent.sigev_signo = SIGIO;  ab.aio_sigevent.sigev_value.sival_ptr = &ab;

線程

  acb.aio_sigevent.sigev_notify = SIGEV_THREAD;  acb.aio_sigevent._sigev_un._sigev_thread._function = rw;  acb.aio_sigevent._sigev_un._sigev_thread._attribute = NULL;  acb.aio_sigevent.sigev_value.sival_ptr = &acb;

可能因為不同版本的標頭檔提供的介面有所不同，網上有些資料說的是acb.aio_sigevent.notify_function，但我在實際應用中沒有找到他的定義。