Re^5: Parallelization of heterogenous (runs itself Fortran executables) code

Addendum: Every Getopt::Std test suite ever distributed Perl, going back to 5.004_04, tests for this behavior. So now I would really like to see your experiments.

I personally believe that you're right. More precisely, you're obviously right. Anyway I probably just tried to add an unknown switch to a cmd line that worked:

C:\temp>runn.pl -q
Unknown option: q
Usage: C:\temp\runn.pl [-n N] [-r] [-v] command arg1 arg2...
Run command arg1, command arg2, etc., concurrently.
Run no more than N processes simultaneously (default 1)
    -r: run commands in random order instead of specified order (unimp
+l.)
    -v: verbose mode

C:\temp>runn.pl -n 2 dir *.txt *.pl -q
exec: No such file or directory at C:\temp\runn.pl line 27.
exec: No such file or directory at C:\temp\runn.pl line 27.
exec: No such file or directory at C:\temp\runn.pl line 27.
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IPB that the latter should exit early printing the usage screen too.

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Re^6: Parallelization of heterogenous (runs itself Fortran executables) code by Dominus (Parson) on Nov 22, 2007 at 05:13 UTC
I suppose it could do that, but the implementation is a bit difficult. The only way I can think of to do it reliably is to have the parent open a pipe to the child so that the child can communicate back the `errno` from the failed `exec`. And I would need to go over every possible value of `errno` and decide which ones warranted an early exit and which ones didn't. It seems like a complicated issue. Anyway, it's definitely a feature I haven't needed yet. A few years back I did a review of a couple of dozen programs I'd written and put in my `~/bin` directory, and the overwhelming majority of them were over-featurized, not under-featurized. I learned that I had wasted a lot of work on features I didn't need. So these days I try to leave out as many features as possible until I'm sure I need them. The original version of this program left `-v` unimplemented, but I kept wishing for it, so eventually I put it in. The original version of this program left `-r` unimplemented, but I haven't yet wished for it, so I haven't put it in yet. Win! It occurs to me now that if I did decide that I wanted the `-r` option, the right way to get it would be to write a separate `shuffle` utility that shuffles its arguments and prints them in random order. Then instead of `runN -r ...` I could runN `shuffle ...`. Win! Similarly, it has occurred to me more than once that the program completely fails to report the exit status of the subprocesses. Your suggestion is part of that. But I haven't needed to find out the exit status of the subprocesses, so I haven't tried to fix that. -- Mark Dominus Perl Paraphernalia	[reply]
Re^7: Parallelization of heterogenous (runs itself Fortran executables) code by blazar (Canon) on Nov 22, 2007 at 10:33 UTC
So these days I try to leave out as many features as possible until I'm sure I need them. I personally believe that's the discipline people call YAGNI.	[reply]


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