in reply to Can't get Win32::Create::Process() parent to exit before it's children

Use 

system( 1, $CMDLine);

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  • Comment on Re: Can't get Win32::Create::Process() parent to exit before it's children
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Re^2: Can't get Win32::Create::Process() parent to exit before it's children
by AlphaGrey (Initiate) on Jan 21, 2010 at 08:30 UTC
    Thanks for responding. Late last night I solved the problem. Just for everyone's information and possible future use I will describe the solution. First off I tried calling system with the first parameter of '1', which was supposed to work, by asynchronously creating the new process and returning...but it didn't work either. Also system() is supposed to return the child PID, but it doesn't with the version of PERL that my system is running...it returns a process handle ID. Here is my PERL version. 
    This is perl, v5.8.7 built for MSWin32-x86-multi-thread

Copyright 1987-2005, Larry Wall

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    Here is what I tried, and it didn't work. The parent process didn't return 0, until the child process exited. 
    $ChildPID = system 1, $CMDLine;
   my $Lock = Glck->new($ResName);
   LOG_MSG("I", "Online.pl is about to exit with 0.", 52099);
   exit (0);

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    The solution that worked is this. I went back to using Win32::Process::Create( ) but called it with the DETACHED_PROCESS creation flag set. And this worked as I wanted it to. Online.pl called Create() and then returned '0' back to my server. 
    require Win32::Process;
    
    my $ParentPID;
    
    $ParentPID = $$;
    LOG_MSG("I", "ParentPID = $ParentPID before creating child.", 5209
+9, $ParentPID);
    
    Win32::Process::Create($ChildProc, $CMD, $CMDLine, 0, DETACHED_PRO
+CESS, $CWD) || LOG_MSG("E", "Could not spawn child: $!", 52099);
        
    $ChildPID = $ChildProc->GetProcessID();
    LOG_MSG("I", "ChildPID = $ChildPID", 52099, $ChildPID);
    my $Lock = Glck->new($ResName);
    $Lock->lock_mk($ChildPID);
    LOG_MSG("I", "Online.pl is about to exit with 0.", 52099);
    exit (0);

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    Thanks for looking into this problem for me, I hope this solution helps some of you. I am sure that I will require all of your assistance in the future ;-)
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      Thanks very much for posting this solution - you solved my problem as well!!!

      I had tried Win32::Process::Create(), and saw mention of the DETACHED_PROCESS flag, but had not yet tried it and wasn't sure how to specify it (as which parameter).

      I had spent a day or so trying different combinations of things trying to get this to work. If my child process was a Windows-type application, the parent exited. But if the child was a console-type application, the parent would wait for it. Upon specifying the DETACHED_PROCESS flag as in your example, the console-type application is now spawned and the parent exits.

      Eric S.
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