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Command Console (NT Workstation) Dos Box

Posted on 2000-04-07
Medium Priority
Last Modified: 2010-05-02

I wish to run a process from the command line and return to the same command console some output. E.g.

C:\>  myprocess.exe /?

myprocess Help
   -a command line argument


I'm not new to VB but this one gets me every time.

Can anyone help????


Question by:Jamsie
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LVL 10

Expert Comment

ID: 2693841
Impossible in VB, sorry.

You can create a console app in VB alright, BUT this console app will create *it's own* console into which you can direct stdIN and Output, but you cannot redirect this to the CMD.EXE from which you originally started the program YourVBProgram.exe


There's also been an article about this in a recend VB Programmers Journal, but I don't remember which one it was. But trust me on this one.

If you're happy with an application that creates its own console then let me know but from your question I'd say you won't be. In that case you'll have to resign yourself to the fact that you cannot do this.

Please don't shoot the messenger :o)
LVL 10

Expert Comment

ID: 2693864
PS - if you are happy with a console that is created in a new process, check out this example

With thanks to ameba!

>1) is it possible to make console programs with VB6
Yes. See Goto Samples, smpConsole


Expert Comment

ID: 2694581
Would you be willing to start the console from within VB, then use a batch file to execute the program in the console Window?  You can do that.
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Expert Comment

ID: 2694745
If you have to use the original consil you can use AppActivate to set focus to it and use sendkeys to control it.  <smile>
LVL 43

Expert Comment

ID: 2700162
With thanks to someone (mcrider I think) the following code in a module, compiled will take any VB app and convert it into a dos executable. This will run in the console window in which it is started, you can then use the writeconsole/writefile api calls as the smpConsole example shows to return text to the window.

' ------------------------------------------------------
' MakeConsole.BAS -- Copyright (c) Slightly Tilted Software
' By: L.J. Johnson       Date: 11-30-1997
' Comments:    Contains MAIN(), plus the function
'              which take a standard VB 5.0 EXE (  or VB 6.0 ! )
'              and change it to a 32-bit console app
' ------------------------------------------------------
Option Explicit
Option Base 1
DefLng A-Z

Private Const GENERIC_READ                As Long = &H80000000
Private Const OPEN_EXISTING               As Long = 3&
Private Const FILE_ATTRIBUTE_NORMAL       As Long = &H80&

Private Const SCS_32BIT_BINARY = 0&
Private Const SCS_DOS_BINARY = 1&
Private Const SCS_WOW_BINARY = 2&
Private Const SCS_PIF_BINARY = 3&
Private Const SCS_POSIX_BINARY = 4&
Private Const SCS_OS216_BINARY = 5&

Private Const constMsgTitle = "Make Console App"

' ---------------------------------------------
' Windows API calls
' ---------------------------------------------
Public Declare Sub CopyMem _
   Lib "kernel32" Alias "RtlMoveMemory" _
   (dst As Any, src As Any, ByVal Size As Long)
Private Declare Function CloseHandle _
   Lib "kernel32" _
   (ByVal hObject As Long) As Long
Private Declare Function CreateFile _
   Lib "kernel32" Alias "CreateFileA" _
   (ByVal lpFileName As String, _
    ByVal dwDesiredAccess As Long, _
    ByVal dwShareMode As Long, _
    ByVal lpSecurityAttributes As Long, _
    ByVal dwCreationDisposition As Long, _
    ByVal dwFlagsAndAttributes As Long, _
    ByVal hTemplateFile As Long) As Long

Public Sub Main()
   Dim strCmd              As String
   Dim strMsg              As String
   Dim strRtn              As String
   strCmd = Command$
   If Trim$(strCmd) = "" Then
      strMsg = "You must enter the name of a VB 5.0 standard executable file."
      MsgBox strMsg, vbExclamation, constMsgTitle
      If InStr(1, strCmd, ".", vbTextCompare) = 0 Then
         strCmd = strCmd & ".EXE"
      End If
      If Exists(strCmd) = True Then
         strRtn = SetConsoleApp(strCmd)
         MsgBox strRtn, vbInformation, constMsgTitle
         strMsg = "The file, " & Trim$(strCmd) & ", does not exist."
         MsgBox strMsg, vbCritical, constMsgTitle
      End If
   End If
End Sub

Private Function SetConsoleApp(xstrFileName As String) As String
   Dim lngFileNum          As Long
   Dim ststrMZ_Header      As String * 512
   Dim strMagic            As String * 2
   Dim strMagicPE          As String * 2
   Dim lngNewPE_Offset     As Long
   Dim lngData             As Long
   Dim strTmp              As String
   Const PE_FLAG_OFFSET    As Long = 93&
   Const DOS_FILE_OFFSET   As Long = 25&
   ' ---------------------------------------------
   ' See if file actually exists
   ' ---------------------------------------------
   strTmp = Trim$(Dir$(xstrFileName))
   If Len(strTmp) = 0 Then
      SetConsoleApp = "Failed -- The file, " & xstrFileName & ", does not exist!"
      GoTo ExitCheck
   End If
   ' ---------------------------------------------
   ' Get a free file handle
   ' ---------------------------------------------
   On Error Resume Next
   lngFileNum = FreeFile
   Open xstrFileName For Binary Access Read Write Shared As lngFileNum
   ' ---------------------------------------------
   ' Get the first 512 characters from from file
   ' ---------------------------------------------
   Seek #lngFileNum, 1
   Get lngFileNum, , ststrMZ_Header
   ' ---------------------------------------------
   ' Look for the "magic header" values "MZ"
   ' If it doesn't exist, then it's not an EXE file
   ' ---------------------------------------------
   If Mid$(ststrMZ_Header, 1, 2) <> "MZ" Then
      SetConsoleApp = "Failed -- File is not an executable file."
      GoTo ExitCheck
   End If
   ' ---------------------------------------------
   ' Check to see if it's a MS-DOS executable
   ' ---------------------------------------------
   CopyMem lngData, ByVal Mid$(ststrMZ_Header, DOS_FILE_OFFSET, 2), 2
   If lngData < 64 Then
      SetConsoleApp = "Failed -- File is 16-bit MSDOS EXE file."
      GoTo ExitCheck
   End If
   ' ---------------------------------------------
   ' Get the offset for the new .EXE header
   ' ---------------------------------------------
   CopyMem lngNewPE_Offset, ByVal Mid$(ststrMZ_Header, 61, 4), 4
   ' ---------------------------------------------
   ' Get the "magic" header (NE, LE, PE)
   ' ---------------------------------------------
   strMagic = Mid$(ststrMZ_Header, lngNewPE_Offset + 1, 2)
   strMagicPE = Mid$(ststrMZ_Header, lngNewPE_Offset + 3, 2)
   Select Case strMagic
      ' ---------------------------------------------
      ' Check for NT format
      ' ---------------------------------------------
      Case "PE"
         If strMagicPE <> vbNullChar & vbNullChar Then
            SetConsoleApp = "Failed -- File is unknown 32-bit NT executable file."
            GoTo ExitCheck
         End If
         ' ---------------------------------------------
         ' Get the subsystem flags to identify NT
         '     character-mode
         ' ---------------------------------------------
         lngData = Asc(Mid$(ststrMZ_Header, lngNewPE_Offset + PE_FLAG_OFFSET, 1))
         If lngData <> 3 Then
            On Error Resume Next
            Err.Number = 0
            Seek #lngFileNum, lngNewPE_Offset + PE_FLAG_OFFSET
            Put lngFileNum, , 3
            If Err.Number = 0 Then
               SetConsoleApp = "Success -- Converted file to console app."
               SetConsoleApp = "Failed -- Error converting to console app: " & Err.Description
            End If
            SetConsoleApp = "Failed -- Already a console app"
         End If
      Case Else
         SetConsoleApp = "Failed -- Not correct file type."
   End Select

   ' ---------------------------------------------
   ' Close the file
   ' ---------------------------------------------
   Close lngFileNum
   On Error GoTo 0
End Function

Public Function Exists(ByVal xstrFullName As String) As Boolean
On Error Resume Next       ' Don't accept errors here
   Const constProcName     As String = "Exists"
   Dim lngFileHwnd         As Long
   Dim lngRtn              As Long

   ' ------------------------------------------
   ' Open the file only if it already exists
   ' ------------------------------------------
   lngFileHwnd = CreateFile(xstrFullName, _
                            GENERIC_READ, 0&, _
                            0&, OPEN_EXISTING, _
                            FILE_ATTRIBUTE_NORMAL, 0&)
   ' ------------------------------------------
   ' If get these specific errors, then
   '     file doesn't exist
   ' ------------------------------------------
   If lngFileHwnd = 0 Or lngFileHwnd = -1 Then
      Exists = False
      ' Success -- Must close the handle
      lngRtn = CloseHandle(lngFileHwnd)
      Exists = True
   End If

On Error GoTo 0
End Function
LVL 10

Expert Comment

ID: 2700212

As far as I can tell that code does *not* change your VB program into a console program. What it seems to allow you do is run an existing DOS .exe through your VB front end or something like that.

Am I missing something.

PS -
Jamsie, this is *not* a newsgroup. We've provided some information, it would be appreciated if you would acknowledge receipt and tell us what you think of it. If one of us managed to answer your question, please grade the answer.
LVL 43

Expert Comment

ID: 2700240
caraf_g, perhaps I didn't make it's use clear, if you create an application in VB, Using no forms, but using the Win32 console api calls.

Using the code above, create an executable called MakeVBCon.exe. In a command prompt type

MakeVBCon MyApplication.exe

where MyApplicaton.exe is the executable created for the program written as a console.

This will convert the second exe into a console application.

Try it out, it works! I am using it to create a program which will run in a telnet session from a DOS 5.0 RF scanner handset.
LVL 10

Expert Comment

ID: 2700323
OK.. see my comment of Friday, April 07 2000 - 03:46PM IST

Take the example and compile it. This will create a "console" application.

Start an MS-DOS prompt. Manoeuvre to the correct directory and run the above console application. It will work just like a console, but it will be started in a new window, not in the DOS window from which it was originally called.

So far so good, that was what I was talking about so far...

Then, I took your example program and created it. I ran it against the "console" app described above. It said "Success" (etc).

Now, if I try to run the "console" app, indeed, no second window is opened. But I can't see the original console app anymore. The DOS window from which I started it just seems to "hang".

Still missing something...
LVL 43

Expert Comment

ID: 2700359
caraf_g, with the smpConsole example, change the OpenConsole procedure as below:

Public Function OpenConsole(Capt As String)
'    If AllocConsole() Then
        SetConsoleTitle Capt
        hInConsole = GetStdHandle(STD_INPUT_HANDLE)
        hOutConsole = GetStdHandle(STD_OUTPUT_HANDLE)
'        If hOutConsole = 0 Then
'            FreeConsole
'        Else
'            SetConsoleCtrlHandler AddressOf ConsoleHandler, True
'            OpenConsole = True
'        End If
'    End If
End Function

This doesn't create a new console but gets the handles to the current one instead. I have just tried it out and get the same results as the original example but in the original console window.
LVL 10

Expert Comment

ID: 2700604
Wow... I stand corrected!

Jamsie. You better do the decent thing and give TimCottee a straight "A"
LVL 43

Accepted Solution

TimCottee earned 300 total points
ID: 2700633
Thanks for the vote of confidence, I have to admit it is not all my own work but I have found it ***VERY*** useful!

Author Comment

ID: 2703153
Thanks Chaps for the help,

It's saved my life.

Sorry about being slow to get back to TimCotte and administer them there points and a deserved Grade **A**

I've got a couple of apps using this stuff already.  Very Easy to Use.


LVL 10

Expert Comment

ID: 2703173

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