[Chicago-talk] trouble caputuring return value

[Richard Reina]

Shlomi,

Thanks for your reply. Is this something complicated to do?  If it is I just opt to save the input to a file and have the 1st program open the file to get it.  I was just wondering if you had an idea how steep of a learning curve I have in front of me.

Thanks,

Richard


---- Chicago.pm chatter <chicago-talk at pm.org> wrote:
>
> Hi Richard!
> 
> On Wednesday 31 Mar 2010 15:37:16 Richard Reina wrote:
> > I have a program that opens a separate terminal and prompts the user for
> > some information.  However, for some reason I can't seem to capture the
> > return value.  Does anyone happen to know why the value returned by
> > get_info.pl is not getting returned? Any help would really be appreciated.
> > 
> > Thanks
> > Richard
> > 
> > #!/usr/bin/perl -w
> > 
> > use strict;
> > my $info;
> > 
> > system(q{gnome-terminal --geometry=80x12-0-30 -x perl -e 'require
> > "./get_info.pl"; ($info) = get_input();'});
> 
> You should not expect Perl to assign to a variable in the main program by 
> evaluating an assignment to its name in a different process. To communicate 
> with a child process you need inter-process communications, such as anonymous 
> pipes, sockets, named pipes, System V IPC, mmap, using the file-system for 
> that, etc. Please read a little about UNIX multi-processing basics (a lot of 
> which is also relevant to Windows and other operating systems). 
> 
> > print $info . "\n";
> > 
> > 
> > <<<<<<< get_info.pl >>>>>>>>
> > #!/usr/bin/perl -w
> > 
> > use strict;
> > 
> > print "Enter Info\n";
> > chomp (my $info = <STDIN>);
> > 
> > return $info;
> 
> You cannot use return to return an arbitrary Perl value from a program. It 
> only works for functions. As far as C and UNIX are concerned, everything that 
> comes out of a process must be in sequences of octets. You need to use 
> "print()" on something to emit it to the outside somehow.
> 
> Regards,
> 
> 	Shlomi Fish
> 
> -- 
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> Shlomi Fish       http://www.shlomifish.org/
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