Question

这是我的设计;

1）初始化AIO控制块;

memset(&m_ReadBuffer, 0, sizeof(struct aiocb));
m_ReadBuffer.aio_fildes = dup(m_Socket);
m_ReadBuffer.aio_buf = NULL; /* Not yet */
m_ReadBuffer.aio_nbytes = 0;
m_ReadBuffer.aio_offset = 0;
m_ReadBuffer.aio_reqprio = 0;
m_ReadBuffer.aio_lio_opcode = LIO_READ;

m_ReadBuffer.aio_sigevent.sigev_notify = SIGEV_THREAD;
m_ReadBuffer.aio_sigevent.sigev_value.sival_ptr = (void *) this;
m_ReadBuffer.aio_sigevent.sigev_notify_function = OnReadFinished;
m_ReadBuffer.aio_sigevent.sigev_notify_attributes = NULL;

2）然后触发异步读取操作;

int RetVal = aio_read(&m_ReadBuffer);

if (RetVal != 0)
    return false;
return true;

3）这是我的完成程序;

static void OnReadFinished(sigval_t pArg)
{
    ClassX *pTransport = (ClassX *) pArg.sival_ptr;

    // aio_error returns 0 if the request completed successfully
    int dwError = aio_error(&pTransport->m_ReadBuffer);
    int32_t cbTransferred = 0;

    // Did the request completed successfully
    if (dwError == 0) {
        // Cool, request completed, get the final retrun value.
        cbTransferred = aio_return(&pTransport->m_ReadBuffer);
    }
    else {
        // the request NOT completed, resheduling the reading process..
        // ***HERE: I'm getting "Resource unavailable temporarily***
        if (false == aio_read(&m_ReadBuffer))
            return;
    }

    // ... some codes ..
    return;
}

4）在AIO完成例程中，我在空闲时间内重复“资源暂时不可用”，但是当另一方发送内容时，我可以读取正确的数据。我认为Linux内核存在一个错误。如果套接字中没有数据，则不应使用“资源暂时不可用”错误调用AIO完成例程。它浪费了不必要的时间..

提前致谢

我在RedHat中的SIGEV_THREAD的aio_read完成例程中得到“资源暂时不可用”

0 个答案: