Solved

suspend flow until a child process completes

Posted on 2004-03-29
7
155 Views
Last Modified: 2010-05-02
here's the psuedo code:

from inside a running exe:

for each row in dataset
   create a new process (from a console exe) with parameters based on datarow
next

currently what is happening is that i get multiple instances of the console.exe but what I want is for one instance to run (takes about 10 minutes) then go and process the next row of the dataset.

does anyone know how to wait for the new process to complete before continuing to the next line of code?

Thank you,

Jon
0
Comment
Question by:jonleehacker
7 Comments
 
LVL 13

Expert Comment

by:crazyman
ID: 10711819
How are you starting the New process?
Is this .NET or VB6?
0
 
LVL 4

Expert Comment

by:sokolovsky
ID: 10712063
Look at this code:

Const INFINITE = &HFFFF
Const STARTF_USESHOWWINDOW = &H1
Private Enum enSW
    SW_HIDE = 0
    SW_NORMAL = 1
    SW_MAXIMIZE = 3
    SW_MINIMIZE = 6
End Enum
Private Type PROCESS_INFORMATION
    hProcess As Long
    hThread As Long
    dwProcessId As Long
    dwThreadId As Long
End Type
Private Type STARTUPINFO
    cb As Long
    lpReserved As String
    lpDesktop As String
    lpTitle As String
    dwX As Long
    dwY As Long
    dwXSize As Long
    dwYSize As Long
    dwXCountChars As Long
    dwYCountChars As Long
    dwFillAttribute As Long
    dwFlags As Long
    wShowWindow As Integer
    cbReserved2 As Integer
    lpReserved2 As Byte
    hStdInput As Long
    hStdOutput As Long
    hStdError As Long
End Type
Private Type SECURITY_ATTRIBUTES
    nLength As Long
    lpSecurityDescriptor As Long
    bInheritHandle As Long
End Type
Private Enum enPriority_Class
    NORMAL_PRIORITY_CLASS = &H20
    IDLE_PRIORITY_CLASS = &H40
    HIGH_PRIORITY_CLASS = &H80
End Enum
Private Declare Function CreateProcess Lib "kernel32" Alias "CreateProcessA" (ByVal lpApplicationName As String, ByVal lpCommandLine As String, lpProcessAttributes As SECURITY_ATTRIBUTES, lpThreadAttributes As SECURITY_ATTRIBUTES, ByVal bInheritHandles As Long, ByVal dwCreationFlags As Long, lpEnvironment As Any, ByVal lpCurrentDriectory As String, lpStartupInfo As STARTUPINFO, lpProcessInformation As PROCESS_INFORMATION) As Long
Private Declare Function WaitForSingleObject Lib "kernel32" (ByVal hHandle As Long, ByVal dwMilliseconds As Long) As Long
Private Function RunAndWait(ByVal App As String, ByVal WorkDir As String, dwMilliseconds As Long, ByVal start_size As enSW, ByVal Priority_Class As enPriority_Class) As Boolean
    Dim pclass As Long
    Dim sinfo As STARTUPINFO
    Dim pinfo As PROCESS_INFORMATION
    'Not used, but needed
    Dim sec1 As SECURITY_ATTRIBUTES
    Dim sec2 As SECURITY_ATTRIBUTES
    'Set the structure size
    sec1.nLength = Len(sec1)
    sec2.nLength = Len(sec2)
    sinfo.cb = Len(sinfo)
    'Set the flags
    sinfo.dwFlags = STARTF_USESHOWWINDOW
    'Set the window's startup position
    sinfo.wShowWindow = start_size
    'Set the priority class
    pclass = Priority_Class
    'Start the program
    If CreateProcess(vbNullString, App, sec1, sec2, False, pclass, _
    0&, WorkDir, sinfo, pinfo) Then
        'Wait
        WaitForSingleObject pinfo.hProcess, dwMilliseconds
        RunAndWait = True
    Else
        RunAndWait = False
    End If
End Function
Private Sub Form_Load()
    Call RunAndWait("cmd.exe", "C:\", INFINITE, SW_NORMAL, HIGH_PRIORITY_CLASS)
    MsgBox ("Child Application is closed")
End Sub
0
 
LVL 1

Author Comment

by:jonleehacker
ID: 10714438
Hi Everyone,

The program is in .Net (thank god! by the look of the code that sokolovsky posted).

I have discovered the answer on my own and it is very simple.

            Dim newProcess As New System.Diagnostics.Process
            newProcess.StartInfo.FileName = "notepad.exe"
            newProcess.StartInfo.UseShellExecute = False
            newProcess.StartInfo.Arguments = "text.txt"
            newProcess.StartInfo.RedirectStandardOutput = False
            'Don't show a command prompt window
            newProcess.StartInfo.CreateNoWindow = True
            newProcess.Start()
            newProcess.WaitForExit()       <--*****************This does the trick
            newProcess.Dispose()

Take care,

Jon
0
 
LVL 4

Expert Comment

by:sokolovsky
ID: 10716295
>The program is in .Net (thank god! by the look of the code that sokolovsky posted).
:)
0
 
LVL 5

Accepted Solution

by:
Netminder earned 0 total points
ID: 11256523
User resolved; closed, 125 points refunded.

Netminder
Site Admin
0

Featured Post

Announcing the Most Valuable Experts of 2016

MVEs are more concerned with the satisfaction of those they help than with the considerable points they can earn. They are the types of people you feel privileged to call colleagues. Join us in honoring this amazing group of Experts.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

Have you ever wanted to restrict the users input in a textbox to numbers, and while doing that make sure that they can't 'cheat' by pasting in non-numeric text? Of course you can do that with code you write yourself but it's tedious and error-prone …
Article by: Martin
Here are a few simple, working, games that you can use as-is or as the basis for your own games. Tic-Tac-Toe This is one of the simplest of all games.   The game allows for a choice of who goes first and keeps track of the number of wins for…
Get people started with the process of using Access VBA to control Outlook using automation, Microsoft Access can control other applications. An example is the ability to programmatically talk to Microsoft Outlook. Using automation, an Access applic…
This lesson covers basic error handling code in Microsoft Excel using VBA. This is the first lesson in a 3-part series that uses code to loop through an Excel spreadsheet in VBA and then fix errors, taking advantage of error handling code. This l…

786 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question