system call question

[J. Smith]

If I call an external program like so:
system("$bfish") or warn ("$!");
# Everything is ok

But when I pass parameters like so:
system("$bfish","/E","/I:$file","/O:$file.fish","/Q","/P:$bfishpwd") or
warn("$!");
# I get the "Warning: Something's wrong ....", but it still works.

If I use die instead of warn, the program obviously dies.
So can someone tell me what's going on?

I get a warning, but it still works.
Am I passing parameters the wrong way?

I'm running WinXP pro.

Thanks.

[Tad McClellan]

J. Smith <noemailplease@defunked.net> wrote:

> system("$bfish") or warn ("$!");

^ ^ ^ ^
^ ^ ^ ^

perldoc -q vars

What's wrong with always quoting "$vars"?


system($bfish) or warn($!);


--
Tad McClellan SGML consulting
[email]tadmc@augustmail.com[/email] Perl programming
Fort Worth, Texas

[Eric Bohlman]

"J. Smith" <noemailplease@defunked.net> wrote in
news:vm744i46nl3h6b@corp.supernews.com:

> If I call an external program like so:
> system("$bfish") or warn ("$!");
> # Everything is ok
>
> But when I pass parameters like so:
> system("$bfish","/E","/I:$file","/O:$file.fish","/Q","/P:$bfishpwd") or
> warn("$!");
> # I get the "Warning: Something's wrong ....", but it still works.

That means that the external program is returning a non-zero exit status in
the second case, but not the first. To find out why, you need to determine
the exit status you're getting (perldoc -f system will tell you how) and
then find out what the external program means by it.

Since system() doesn't set $!, the text of the warning you print is going
to be meaningless and misleading.

>
> If I use die instead of warn, the program obviously dies.
> So can someone tell me what's going on?
>
> I get a warning, but it still works.
> Am I passing parameters the wrong way?
>
> I'm running WinXP pro.
>
> Thanks.
>
>

[John J. Trammell]

On Sat, 13 Sep 2003 16:48:05 -0500, J. Smith <noemailplease@defunked.net> wrote:

> If I call an external program like so:
> system("$bfish") or warn ("$!");
> # Everything is ok
>
> But when I pass parameters like so:
> system("$bfish","/E","/I:$file","/O:$file.fish","/Q","/P:$bfishpwd") or
> warn("$!");
> # I get the "Warning: Something's wrong ....", but it still works.
>
> If I use die instead of warn, the program obviously dies.
> So can someone tell me what's going on?
>

Read "perldoc -f system", paying close attention to system()'s return
value. And what's with all the useless quotes? Those things don't
grow on trees ya know!

[John W. Krahn]

"J. Smith" wrote:

>
> If I call an external program like so:
> system("$bfish") or warn ("$!");
> # Everything is ok
>
> But when I pass parameters like so:
> system("$bfish","/E","/I:$file","/O:$file.fish","/Q","/P:$bfishpwd") or
> warn("$!");
> # I get the "Warning: Something's wrong ....", but it still works.
>
> If I use die instead of warn, the program obviously dies.
> So can someone tell me what's going on?
>
> I get a warning, but it still works.
> Am I passing parameters the wrong way?

If you read the documentation for the system function you will see that
it DOES NOT return true on success and false on failure as you seem to
assume.

perldoc -f system


John
--
use Perl;
program
fulfillment

[J. Smith]

Thank you Eric.
All is well now. No more warnings.
Super!!

"Eric Bohlman" <ebohlman@earthlink.net> wrote in message
news:Xns93F5B60D2EA48ebohlmanomsdevcom@130.133.1.4 ...

> "J. Smith" <noemailplease@defunked.net> wrote in
> news:vm744i46nl3h6b@corp.supernews.com:
>

> > If I call an external program like so:
> > system("$bfish") or warn ("$!");
> > # Everything is ok
> >
> > But when I pass parameters like so:
> > system("$bfish","/E","/I:$file","/O:$file.fish","/Q","/P:$bfishpwd") or
> > warn("$!");
> > # I get the "Warning: Something's wrong ....", but it still works.

>
> That means that the external program is returning a non-zero exit status

in

> the second case, but not the first. To find out why, you need to

determine

> the exit status you're getting (perldoc -f system will tell you how) and
> then find out what the external program means by it.
>
> Since system() doesn't set $!, the text of the warning you print is going
> to be meaningless and misleading.
>
>

> >
> > If I use die instead of warn, the program obviously dies.
> > So can someone tell me what's going on?
> >
> > I get a warning, but it still works.
> > Am I passing parameters the wrong way?
> >
> > I'm running WinXP pro.
> >
> > Thanks.
> >
> >

>