这个回调函数的作用是是什么？

haian_bch

这个回调函数的作用是是什么？ [复制链接]

函数如下：
typedef void (CALLBACK DRVCALLBACK)(HANDLE hdrvr, UINT uMsg, DWORD dwUser, DWORD dw1, DWORD dw2);

typedef DRVCALLBACK FAR *LPDRVCALLBACK;
typedef DRVCALLBACK     *PDRVCALLBACK;

该函数在程序中申明为： DRVCALLBACK*    m_pfnCallback;

RemoveCompleteBlocks函数对传输完成块进行清空处理，该函数中回调函数的作用是什么？

VOID   
CWavehdrQueue::RemoveCompleteBlocks(void)
{
    PWAVEHDR pwh;
    while (m_pHead != NULL && IS_BUFFER_DONE(m_pHead))  
        {
        ASSERT(m_pHead != m_pCurrent);  // By definition, the current block is not complete.
        pwh = m_pHead;
        m_pHead = pwh->lpNext;
        if (m_pHead == NULL)
                {
            // keep m_pTail consistent.
            m_pTail = NULL;
        }
        pwh->lpNext = NULL;
        MARK_BUFFER_DEQUEUED(pwh);
        //
        // Make the callback function call to the Wave API Manager
        //

                // call back into the waveform API manager, which takes care of marshalling the callback
                // to the application.
                // Note that the application callback could conceivably trigger events
                // that would lead to the stream being closed before the callback returns
                // In that case, the driver must close gracefully and defer
                // the deletion of the underlying objects until after the callback
                // has returned.
                // This is accomplished in the stream context interrupt handler with
                // reference counting.
        m_pfnCallback(m_hWave, m_uMsg, m_dwInstance, (DWORD) pwh, 0);     //调用
                count--;//cren
                RETAILMSG(ZONE_CALLBACK, (TEXT("HDRQ: Sending callback hwav=%08x inst=%08x pwh=%08x, %d \r\n"), m_hWave, m_dwInstance, pwh, count));
    }   
}

Jonsen_yang

对于结帖率：0.00% 的，一概不回答!!!

stonepal

顶LS

chna0410

引用 1 楼 91program 的回复:
对于结帖率：0.00% 的，一概不回答!!!

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