[perl #60848] fork-exec-pipe issue in perl 5.8.6 on linux

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Hi,
I am facing a problem related to fork-exec-pipe sequence in perl on linux.
(perl version 5.8.6 on fedora linux) I have a piece of perl code on Sun
Solaris system(perl version 5.005_03) which is working absolutely fine.
However when I tried the same code on fedora linux it does not work. I am
copying the part of the code here:

pipe R1, W1; pipe R2, W2;
select((select(W2), $| = 1)[0]); # autoflush output to dotcntl
$chld = fork();
if ($chld == 0)
{
      # Child: execute FORTRAN wrapper.
      print("comes in child \n");
      close R1;
      close W2;
      open(STDIN, "<&R2");
      open(STDERR, ">&W1");
      exec("$PSE_HOME/bin/dotcntl") or print("PSE:ERROR Optimizations not
installed.\n"),
      exit 2;
} else
{
     # Parent: interact with the wrapper.
     close W1;
     close R2; #do the stuff
}
here I expect to get the parent executed first and then child repeatedly. It
works as expected on SunOS however on linux it executes child first - does
nothing, then executes parent and for obvious reasons it hangs. Do you have
any idea about what's going on here. Waiting for the reply.


Thanks,
Shubhangi

• [perl #60848] fork-exec-pipe issue in perl 5.8.6 on linux by Shubhangi
• Re: [perl #60848] fork-exec-pipe issue in perl 5.8.6 on linux by Dominic Dunlop