Re: RISCOS "free" system call

At 20:14 17/01/2003 +1100, Iain 'Spoon' Truskett wrote:
>* Phillip Marsden ([email protected]) [17 Jan 2003 20:09]:
> > Apologies if this has been covered before, but I am a new subscriber,
> > and have not yet got all the FAQ etc.
>
> > I wish to get the amount of free space on a floppy for a copy program
> > which is working from a web page. Not having used Perl modules, I
> > decided to use the RISC OS "free" command via the system function.
>
>Without delving into the Acorn specific modules:
>
>my $free = `free`; # note the backticks.
>
>This puts the output of the free command into the variable $free.
>
>Perhaps check out perlintro on perldoc.com or pick up a copy of
>"Learning Perl"?

Thanks for the speedy response.

Yes, if I had been programming in Unix shell, then this would have been 
done long ago. :o)

The two people I asked before (and who referred me to this list) suggested 
the back-quotes method. I tried it, but it failed, and I tried other 
methods which partially worked. However, with yet another person stating it 
should work, I was determined to investigate to the full.

The solution was to use the 'free' command properly. I had assumed that I 
could give 'free' the full disk specification, but 'free' pre-pends the 
given parameter with 'ADFS::'. 'Free' had then failed because it did not 
understand "ADFS::ADFS::0". 'Free' did not send the error message back to 
my Perl variable - it sent it elsewhere, so I can only assume that RISC OS 
has the equivalent of stderr. With nothing being placed in the Perl 
variable, I thought that there was a problem with back-quotes.

(I also learned that 'free' does not handle IDEFS on my hard drive. IDEFS 
must have its own version of 'free').

Thanks for the push to find the real reason behind my earlier failures.

-- 

Regards, Phillip Marsden.

[email protected]