Re^2: Modules which improve system() ?

[pjf]

in reply to Re: Modules which improve system() ?
in thread Modules which improve system() ?

I'm specifically after a module that makes it dead simple to call system() for the most simple cases, and still get proper error-handling. What I essentially want is Fatal for system().

That means we're not capturing output, and we're not doing complicated pipelines. If you want a module that handles all that and more, then there's IPC::Run. It's complete, but it's not simple.

What's proper-error handling for the most simple cases? Well, if your program never started, that's an error. If it got killed by a signal or dumped core, then you probably didn't expact that, so that's an error too. If it returns a non-zero exit status, then that's also an error unless you pass an argument to say otherwise.

As for efficiency, this is a clear case where correctness should easily trump speed. system() is slow to begin with, since there's all that fork-and-exec'ing going on under the hood. Having error-checking that's hard to get wrong (ie, exceptions), and having meaningful error messages (instead of die "Ooops! $! - $?") is going to be much better for correctness and programmer productivity in the long run.

This is very much a case of wanting something that makes simple things easy. We've already got many ways of making the hard things possible.

Cheerio,

[xdg]

As I just mentioned in this post, how about IPC::Run3?

From its Pod:

compared to system(), qx'', open "...|", open "|...":

    + redirects more than one file descriptor
    + returns TRUE on success, FALSE on failure
    + throws an error if problems occur in the parent process (or the 
+pre-exec child)
    + allows a very perlish interface to Perl data structures and subr
+outines
    + allows 1 word invocations to avoid the shell easily:

         run3 ["foo"];  # does not invoke shell

    - does not return the exit code, leaves it in $?

So you could use it like this:

eval { run3 $program } or die "Errors running $program";

Its docs leave a bit to be desired, but the current maintainer might be willing to take some doc patches...

[adamk]

I concur with my learned friend on IPC::Run3 as a direct replacement to system(), although it can't do some of the more interactive tricks of IPC::Run.

Morover, IPC::Run3 works on every single platform flawlessly, and so it makes for a very safe dependency. Some of the others do have the odd platform issue.