[vbox-dev] Result and exit code for [VBoxManage guestcontrol execute] without --wait flags

[Andreas Löffler]

Hi Erik,

thanks for your suggestions.

We're aware that VBoxManage at the moment doesn't do an optimal job at 
the moment when it comes to exit codes, e.g. they're somewhat rarely 
used besides 0. Also they often only indicate the bare minimum required 
for getting a shell script to work.

However, if you need to do more advanced work I'd recommend using our 
API instead of using VBoxManage as a client. There you have a much more 
fine-grained control on what happened compared to plain old exit codes 
returned by VBoxManage.

I'll think about the PID output on successful start and the exit code 
handling; both sound like a useful improvement to me. For 4.1 we 
probably won't touch the current behavior, but for the 4.2(.x) branch we 
certainly can improve things a bit.

Regards,

-Andy


On 01.09.2012 20:29, Erik Leunissen wrote:
> Hi,
>
> When not using one of the flags --wait-stdout --wait-stderr or
> --wait-exit to "VBoxManage guestcontrol execute", the current[*]
> behaviour w.r.t. exit code and standard output is:
>
> a. nothing is written to stdout, unless the --verbose flag was specified
> on the command line.
> b. the exit code is invariably 1, indicating failure, even if the
> process was launched successfully.
>
>
> I'd like to propose to change this behaviour as follows:
>
> a. result on stdout is the PID of the newly launched process (just the
> number), without needing to pass the --verbose flag on the command line.
> b. exit code indicates success of program launch (exit code = 0), or
> some failure (exit code<>  0)
>
> Advantages (IMHO) over the current behaviour:
> - correct distinction between success and failure of program launch,
> where real failure cases can be handled specifically.
> - straightforward support for further programmatic control of the newly
> launched process through its PID
>
> Any comments, thoughts ... ?
>
>
> Greetings,
>
> Erik Leunissen.
>
> --
> [*] Version 4.1.18, Host: Linux OpenSuSE 11.4, Guest: Windows Vista
>
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-- 
Kind regards / Mit freundlichen Grüßen

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Andreas Löffler          | VirtualBox Engineering
Senior Software Engineer | Oracle Virtualization

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