Agilent Technologies 4294A - Page 183

Chapter 12 183
Using LAN
Controlling the Agilent 4294A
1. Chapter Title
12. Using LAN 3. Chapter Title
4. Chapter Title
5. Chapter Title
Example 12-5 RecvAscii
Function RecvAscii(dataBuf As String, ByVal maxLength As Integer) As Integer
Dim c As String * 1
Dim length As Integer
dataBuf = ""
While length < maxLength
DoEvents
count = recv(socketId, c, 1, 0) '
If count < 1 Then '
RecvAscii = RECV_ERROR '...................(1)
dataBuf = Chr$(0) '
Exit Function '
End If '
If c = Chr$(10) Then '
dataBuf = dataBuf + Chr$(0) '...................(2)
RecvAscii = NO_ERROR '
Exit Function '
End If '
length = length + count '...................(3)
dataBuf = dataBuf + c '
Wend
RecvAscii = RECV_ERROR
End Function
Disconnection
The subprogram corresponding to disconnection is CloseConnection (Example 12-6).
CloseConnection uses the closesocket function of WinSock API to disconnect communication, and
deletes the socket. The parameter for the closesocket function is Socket Descriptor (input).
Example 12-6 CloseConnection
Sub CloseConnection()
x = closesocket(socketId)
If x = SOCKET_ERROR Then
MsgBox ("ERROR: closesocket = " + Str$(x))
Exit Sub
End If
End Sub
End
The subprogram corresponding to end is EndIt (Example 12-7). EndIt uses the WSACleanup of
WinSock API to disconnect WinSock API. WSACleanup must always be executed at the end of
WinSock.
Example 12-7 EndIt
Sub EndIt()
'Shutdown Winsock DLL
x = WSACleanup()
End Sub