請教各位前輩,
(1)的寫法, 寫到comport, write file 成功之後, 卻要2到3秒, 合理嗎? 是不是我有什麼地方寫錯了?
(2)的寫法, 寫到comport, 失敗, 卻立即回應, 這樣是錯在什麼地方?
==================================================
(1) hCom = CreateFile("COM1", GENERIC_READ|GENERIC_WRITE, 0, NULL, OPEN_EXISTING, 0, NULL);
(2) hCom = CreateFile("COM1", GENERIC_READ|GENERIC_WRITE, 0, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL | FILE_FLAG_OVERLAPPED,, NULL);

// 以下在兩種寫法不變
if(hCom == INVALID_HANDLE_VALUE)
{
return false;
}
DCB dcb;
if(!GetCommState(hCom, &dcb))
{
return false;
}
dcb.BaudRate = 19200;
dcb.ByteSize = 8;
dcb.Parity = ODDPARITY;
dcb.StopBits = ONESTOPBIT;
if(SetCommState(hCom, &dcb) == 0)
{
return false;
}

char sCommandBuf[MAX_COMMAND_NUM];

DWORD dwBytesWritten;
if(!WriteFile(hCom, sCommandBuf, sizeof(sCommandBuf), &dwBytesWritten, NULL))
{
// ng
}
else
{
// ok
}

你好，
(1) 2至3秒並不一定不合理，而且你的baud rate 19200而已，若資料量大的話則有可能數秒。

(2) 第二種寫法FILE_FLAG_OVERLAPPED的參數，會立即回應是正確的!，它本來就是會立即回應。這種寫法較複雜，要自己實作event的處理，詳情google一下應該有不少的文章!

===================引 用 Solaris2005 文 章===================
請教各位前輩,
(1)的寫法, 寫到comport, write file 成功之後, 卻要2到3秒, 合理嗎? 是不是我有什麼地方寫錯了?
(2)的寫法, 寫到comport, 失敗, 卻立即回應, 這樣是錯在什麼地方?
==================================================
(1) hCom = CreateFile("COM1", GENERIC_READ|GENERIC_WRITE, 0, NULL, OPEN_EXISTING, 0, NULL);
(2) hCom = CreateFile("COM1", GENERIC_READ|GENERIC_WRITE, 0, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL | FILE_FLAG_OVERLAPPED,, NULL);

// 以下在兩種寫法不變
if(hCom == INVALID_HANDLE_VALUE)
{
return false;
}
DCB dcb;
if(!GetCommState(hCom, &dcb))
{
return false;
}
dcb.BaudRate = 19200;
dcb.ByteSize = 8;
dcb.Parity = ODDPARITY;
dcb.StopBits = ONESTOPBIT;
if(SetCommState(hCom, &dcb) == 0)
{
return false;
}

char sCommandBuf[MAX_COMMAND_NUM];

DWORD dwBytesWritten;
if(!WriteFile(hCom, sCommandBuf, sizeof(sCommandBuf), &dwBytesWritten, NULL))
{
// ng
}
else
{
// ok
}

------


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謝謝前輩指教, 我試著改BAUD RATE試試看, 感恩!