How do I prevent "end process tree" from terminating the programs mine has started?

Question

I am trying to execute an EXE 'two.exe' from another application 'one.exe' in Delphi XE2 using ShellExecute.

ShellExecute(0, 'open', 'two.exe', nil, nil, SW_NORMAL);

It works perfectly, but whenever I terminate application 'one.exe' (the parent app) from Task Manager's process tab, using the "end process tree" option, the application 'two.exe' also gets terminated.

How can I prevent my ShellExecuted application from getting terminated like this?

I can't reproduce what you're explaining... like you explain: `ShellExecute(Application.Handle, 'open', PWideChar(ExtractFileName(Application.ExeName)), nil, PWideChar(ExtractFilePath(Application.ExeName)), SW_SHOWNORMAL);` Don't kill the other instances... `ShellExecute(0, 'open', PWideChar(ExtractFileName(Application.ExeName)), nil, PWideChar(ExtractFilePath(Application.ExeName)), SW_SHOWNORMAL);` — Whiler, May 15 '12 at 16:39
Are you sure there is not some other interaction between the two apps that would cause the second app to close when the first is closed? — hatchet - done with SOverflow, May 15 '12 at 16:47
I can reproduce it. Exactly as described in the question. In Process Explorer there is a view of the processes that clearly shows the group hierarchy. — David Heffernan, May 15 '12 at 16:50
@DavidHeffernan: I agree with Process Explorer.. but with the regular TaskManager, when I end the process tree, it doesn't kill my child app if my first argument is 0... — Whiler, May 15 '12 at 16:59
`CREATE_NEW_PROCESS_GROUP` looks like the thing to use. But I can't make it work. — David Heffernan, May 15 '12 at 17:04
+1. Just as a note: Unless you know for sure that the file association for a file extension has a specific verb assigned, don't use one. (For instance, .exe in HKCR does not have an `open` verb, it has `run`. You shouldn't use `open`.) Just use `nil` instead when you want the default action to take place, and let Windows figure out what to do; it will automatically open Word document (`.doc`) files, run executables, etc. — Ken White, May 15 '12 at 19:47

score 12 · Answer 1 · edited May 23 '17 at 12:08

12

Ok, not very nice solution... but tested with success ;o)

ShellExecute(0, 'open', 'cmd', 
  PChar('/C  start "" "' + Application.ExeName + '"'), nil, SW_HIDE);

enter image description here

The first is manually launched... his child with regular shellexecute call... The last one, with the shellexecute + cmd trick...

/C explanation

edited May 23 '17 at 12:08

Community

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answered May 15 '12 at 17:41

Whiler

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This is an implementation of the method in my answer. Downside, I guess, is that a command window flashes up for a second. – David Heffernan May 15 '12 at 17:50
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Yes, that's an implemantation of your explanation... but I swear I haven't copied.. I was testing it when you post it and saw it after ;o) – Whiler May 15 '12 at 17:52
Oh I didn't mean to imply that. I just wanted to add an explanation of how this technique works. – David Heffernan May 15 '12 at 17:53
@Tlama Right, I see that now. – David Heffernan May 15 '12 at 18:31
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@Whiler I added something to the code so that it would cope with programs that contain spaces in their names. +1 by the way. – David Heffernan May 15 '12 at 18:32
don't you add too much (or is it the website formating...) (after the start..) – Whiler May 15 '12 at 19:14
try it without the seemingly spurious `""`. You will find that does not work and is interpreted as the window title. Look at `start /?` to understand why. – David Heffernan May 15 '12 at 19:16

David Heffernan · Accepted Answer · 2012-05-15T19:45:00.303

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I think you need to create an intermediate process which in turn spawns two.exe. You then need the intermediate process to terminate immediately, at which point the relationship between the original process and two.exe is broken.

edited May 15 '12 at 19:45

answered May 15 '12 at 17:19

David Heffernan

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After some search without result, I agree as I don't think it's possible to update the [th32ParentProcessID](http://stackoverflow.com/a/1857762/596852) which is probably used by Process Explorer... – Whiler May 15 '12 at 18:18

How do I prevent "end process tree" from terminating the programs mine has started?

2 Answers2