Re: Newbie question - how to return a value from Octave?

[Carlo de Falco]

On 21 Jan 2010, at 16:26, David Aldrich wrote:

> Hi
>
> I am new to Octave. I want to use Octave in an automated build  
> system to run regression tests. Each regression test will be  
> executed by a Matlab function that will return an integer indicating  
> the test result. I need to be able to invoke that function by  
> running Octave, and for Octave to return the function result.
>
> For example, I want to be able to run something like:
>
> C:\> Octave pi
>
> and for the Windows environment variable %ERRORLEVEL% to be set to 3
>
> (an alternative solution in Linux would be acceptable).
>
> Is this possible and what is the exact command line syntax please?
> Best regards
> David

I know nothing about windows, but on any Unix system you can do  
something like

guglielmo.local $ export ERRORLEVEL=`octave -q --eval  
"fprintf('%1.1g',pi)"`
guglielmo.local $ printenv ERRORLEVEL
3
guglielmo.local $ export ERRORLEVEL=`octave -q --eval  
"fprintf('%g',pi)"`
guglielmo.local $ printenv ERRORLEVEL
3.14159

the exact syntax will of course depend on the shell, the above is for  
bash.
On the other hand, depending on your application, launching one  
instance of Octave
any time you need to change the value of an environment variable might  
not be the best
option in terms of efficiency, and you might be rather interested in  
some sort of interprocess
communication mechanism (e.g. pipes, sockets, etc.)

HTH,
c.