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I have a serial comms app that reads data from a COM port. Some items are displayed for monitoring purposes, i.e. we can see the app is running properly and receiving data. Since system the app is running on (NT 4 SP 6A) has a Digi AccelePort 8r 920 boeard installed. It has 8 extra COM ports numbered 3 through 10 (the system itself has the usual 2 ports).
Receiving data from the AccelePort ports works fine in itself, but I get an Illegal function call error (error # 5) in the Thread Create statement of the PortOpen() function. This only happens when I use the ports on the AccelePort - if I use COM1 or COM2 this error does not occur. The really odd thing about it is that the thread is created and runs just fine. My error handling routine pops a message box with the error, but I can see the main dialog getting updated in the background. I even rewrote the error trap to ignore error # 5, and everything worked flawlessly (in the sense that the error doesn't seem to have any noticeable effect).
I wrote a small test app that reads data from the same port but does everything in the main thread - no problems or errors at all.
Any hints & tips as to why this occurs would be very much appreciated. I've included the code below, reducing it as much as possible while making sure it still compiles & runs in case anyone has a similar setup and wants to try it. You don't have to have any inbound data on the port to see the error, but then you'll just have to take my word that the dialog would update if there were any data
Ketil
Here's the code:
Receiving data from the AccelePort ports works fine in itself, but I get an Illegal function call error (error # 5) in the Thread Create statement of the PortOpen() function. This only happens when I use the ports on the AccelePort - if I use COM1 or COM2 this error does not occur. The really odd thing about it is that the thread is created and runs just fine. My error handling routine pops a message box with the error, but I can see the main dialog getting updated in the background. I even rewrote the error trap to ignore error # 5, and everything worked flawlessly (in the sense that the error doesn't seem to have any noticeable effect).
I wrote a small test app that reads data from the same port but does everything in the main thread - no problems or errors at all.
Any hints & tips as to why this occurs would be very much appreciated. I've included the code below, reducing it as much as possible while making sure it still compiles & runs in case anyone has a similar setup and wants to try it. You don't have to have any inbound data on the port to see the error, but then you'll just have to take my word that the dialog would update if there were any data
Ketil
Here's the code:
Code:
#Compile Exe "FORUM.exe"
#Dim All
#Register None
#Option Version4
#Debug Error On
#Include "win32api.inc"
%IDC_STATIC = -1
%IDC_SYSINFO01 = 1201
Declare Function CreateDlg(ByVal hParent As Long) As Long
Declare Function PortOpen() As Long
Global hMain As Long ' handle to main dialog
Global hComm As Long ' handle to COM port
Global hThread As Long ' handle to data receive thread
Global fThreadClose As Long ' flag to close port listen thread
Function PbMain() As Long
Local iDlgMainResult As Long
hMain = CreateDlg(0)
iDlgMainResult = -1
Dialog Show Modeless hMain To iDlgMainResult
If Not IsTrue PortOpen() Then Function = 1: Exit Function
Do
Dialog DoEvents
Loop Until iDlgMainResult = 0
Call PortClose
End Function
Function PortClose() As Long
Local sDummy As String
Local iResult As Long
On Error GoTo PortClose_Error
fThreadClose = %TRUE
Do
Thread Close hThread To iResult
Sleep 0
Loop Until IsTrue iResult
Sleep 1000
If Comm(#hComm, RxQue) Then
Comm Recv #hComm, Comm(#hComm, RxQue), sDummy
End If
Comm Close #hComm
hComm = 0
Function = %TRUE
PortClose_Exit:
Exit Function
PortClose_Error:
Function = %FALSE
MsgBox "PortClose() error # " & Format$(Err)
Resume PortClose_Exit
End Function
Function PortOpen() As Long
On Error GoTo PortOpen_Error
hComm = FreeFile
Comm Open "\\.\COM3" As #hComm
If ErrClear Then Function = %FALSE: Exit Function
Comm Set #hComm, Baud = 9600
Comm Set #hComm, Byte = 8
Comm Set #hComm, Parity = %FALSE
Comm Set #hComm, Stop = 0
Comm Set #hComm, DtrLine = %TRUE
Comm Set #hComm, TxBuffer = 1024
Comm Set #hComm, RxBuffer = 16384
Thread Create ReadPort(hMain) To hThread
Function = %TRUE
PortOpen_Exit:
Exit Function
PortOpen_Error:
Function = %FALSE
MsgBox "PortOpen() error # " & Format$(Err)
Resume PortOpen_Exit
End Function
Function ReadPort(ByVal hWnd As Long) As Long
Local sRecv As String
Local cFrames As Long
Local iRxQue As Long
On Error GoTo ReadPort_Error
Do While IsFalse fThreadClose
ReadPort_Reentry:
iRxQue = Comm(#hComm, RxQue)
If iRxQue < 800 Then Sleep 50: Iterate Loop
Comm Recv #hComm, 800, sRecv
cFrames = cFrames + (Len(sRecv) / 16)
Control Set Text hMain, %IDC_SYSINFO01, Format$(cFrames, ",")
Loop
Function = %TRUE
ReadPort_Exit:
Exit Function
ReadPort_Error:
Function = %FALSE
MsgBox "ReadPort() Error: " & Format$(Err)
Resume ReadPort_Reentry
End Function
Function CreateDlg(ByVal hParent As Long) As Long
Local hDlg As Long
Dialog New hParent,"HI Sensor Reader",0,0,250,203,%DS_MODALFRAME Or %DS_CENTER Or %WS_MINIMIZEBOX Or %WS_CAPTION Or %WS_SYSMENU , To hDlg
Control Add Label, hDlg, %IDC_STATIC,"Frames read",68,160,45,10,%SS_RIGHT Or %WS_VISIBLE Or %WS_CHILD
Control Add TextBox, hDlg, %IDC_SYSINFO01,"",118,160,40,12,%ES_RIGHT Or %WS_DISABLED Or %WS_VISIBLE Or %WS_CHILD Or %WS_TABSTOP,%WS_EX_CLIENTEDGE
Function = hDlg
End Function
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