Neverending exec process

[skiflyer]

Simple code...

Set wshShell = WScript.CreateObject("WScript.Shell")
dirCmd = "cmd /c dir /s /b /O-D buildlog.htm"

Set X = wshShell.Exec(dirCmd)
Do While X.Status = 0
  MsgBox "Looping..." & X.Status
  WScript.Sleep 1000
Loop
MsgBox "Out of loop"

Works great usually, but when the number of matches gets too big (I think around 30-40, not certain though), the process never ends and my program goes into an infinite loop. (MsgBox's only there for debugging purposes).

Anyone have an idea or a workaround?

 

[skiflyer]

Workaround... remove the cmd /c

So, there's the fix... now, can anyone explain to me why this fixes it?

 

[tsuji]

Hello skiflyer,

This is a known "bug" if I may say so. It seems to be delinquant endofstream of the stdout making comspec instance not ending waiting eternally to end.

Generally, do not allow cmd /k or cmd /c or command /k or command /c. For instance:
.exec("ping xxx...")
and
.exec "cmd /k ping xxx..." ' to _avoid_ --- hang

regards - tsuji

 

[skiflyer]

Well, removing the cmd /c worked great on my development machines, but on my production machines I get an error that the file cannot be found.

The file in question being 'dir'

So... still stuck afterall, but a new stuck, anyone know?

 

[PHV]

IMHO, cmd /c is MANDATORY for all internal commands (DIR, SET, ...)

Hope This Help, PH.
Want to get great answers to your Tek-Tips questions? Have a look at FAQ219-2884 or FAQ222-2244

 

[skiflyer]

Ok... then do you have any advice on making it work?

In my case using cmd /c causes a freeze.

 

[tsuji]

skiflyer,

The solution is that you use in these particular case:
wshshell.run dirCmd

regards - tsuji

 

[skiflyer]

But I thought run returns an error code rather than the output of the command... I'll tinker more with run I guess

 

[skiflyer]

So, the only thing crossing my mind is to use wscript.run to dump the results to a file

cmd /c dir /s /b /O-D build.html >> temp.txt

And then read in the contents of that file... but now this is getting to a ridiculous level of complexity.

Before I go down that road, does anyone have another suggestion?

 

[tsuji]

skiflyer,

Complexity is only apparent sometimes. One should not expect having programming paradise where there is always only one-liner to call up a built-in service responding to everybody's any need. Even then, you have a manual of a unmangeable complexity.

- tsuji

 

[skiflyer]

I agree with the concept, but I've yet to find a language where I can't read an output stream directly.

It's an especially large shortcoming with a scripting language where streams and pipes and redirects are used extensively.

 

[tlogan]

Hi! -
I hope skiflyer and tsuji are stil monitoring this thread, but I would appreciate insights from anyone else interested in this problem...

I have the same problem, but I am NOT using cmd. I have virtually identical scripts running an FTP session. One has a large amount of output the other doesn't. The one with a large amount of output hangs, the one with little output doesn't.

I try to hide the FTP from the user and here is code that works in both cases, but I cannot (at least I haven't been able to figure how to) do some rudimentary error checking.

 Set Script=WScript.CreateObject("WScript.Shell")
 Script.Run "ftp -n -s:" & sfName & " 99.99.99.99", 0, True
 scriptfile.Delete True
 set scriptfile = nothing
 set oFSo = nothing

Running it THIS way, I can do some error checking, but the box isn't hidden, which I can live with. THIS is the code that hangs when there is too much data written to stdout

 Set Script=WScript.CreateObject("WScript.Shell")
 set X = Script.Exec("ftp -n -s:" & sfName & " 99.99.99.99")
 Do while X.Status = 0
    WScript.sleep 250
 Loop
 scriptfile.Delete True
 set scriptfile = nothing
 set oFSo = nothing

*** Look for FTP Errrors
 While Not X.StdOut.AtEndOfStream
  sLine = Trim(X.StdOut.ReadLine)
  IF LEft(sLine,10) = "Cmd Failed" or Left(sLine,12) = "Login Failed" or Left(sLine,17) = "No Such Directory" or Right(sline,14) = "File not found"  THen
      MSgBOx "FTP Down Failed with message: " & sLine
      Wscript.quit
  End IF
 Wend

Thnask for any help
TLogan
The man without an interesting moniker

 

[skiflyer]

Hopefully someone else can come in with more complete information... but here's as much as I can offer this morning before the meetings start.

Personally, I've had nothing but trouble with the Exec method... I would stick with the run. And then, I believe, FTP will set a system variable (ERROR_LEVEL I Think) with the error value... so you can use that to check for errors.

I could be wrong, I'm on the VBS guy around here, but that's what the desk next to me is saying anyway.

 

[tsuji]

Hello tlogan,

In your sfname, try put quit as the last line of instruction. Do you still have it pending?

regards - tsuji