求教：VB能不能做这样一个软件
VB能不能做这样一个软件：检测COM端口和网络是否有信号连接，如果这两者没有信号从电脑输出一个信号（USB）触发蜂鸣器。
理论上C++可以实现吗？
谢谢！
没做过COM的东西，不过从其他地方找到一段判断COM是否可用的代码，
模块声明:
程序代码：Option Explicit
Private Type DCB
DCBlength As Long
BaudRate As Long
fBitFields As Long
wReserved As Integer
XonLim As Integer
XoffLim As Integer
ByteSize As Byte
Parity As Byte
StopBits As Byte
XonChar As Byte
XoffChar As Byte
ErrorChar As Byte
EofChar As Byte
EvtChar As Byte
wReserved1 As Integer
End Type
Private Type COMMCONFIG
dwSize As Long
wVersion As Integer
wReserved As Integer
dcbx As DCB
dwProviderSubType As Long
dwProviderOffset As Long
dwProviderSize As Long
wcProviderData As Byte
End Type
Private Declare Function GetDefaultCommConfig Lib "kernel32" _
Alias "GetDefaultCommConfigA" (ByVal lpszName _
As String, lpCC As COMMCONFIG, _
lpdwSize As Long) As Long
代码:
程序代码：
Public Function ComPortExists(ByVal ComPort As Integer) _
As Boolean
'*****************************************************
'EXAMPLE
'Dim bAns As Boolean
'bAns = ComPortExists(1)
'If bans then
'msgbox "Com Port 1 is available
'Else
'msgbox "Com Port 1 is not available
'End if
'*************************************************
Dim udtComConfig As COMMCONFIG
Dim lUDTSize As Long
Dim lRet As Long
lUDTSize = LenB(udtComConfig)
lRet = GetDefaultCommConfig("COM" + Trim(Str(ComPort)) + _
Chr(0), udtComConfig, lUDTSize)
ComPortExists = lRet <> 0
End Function
