in reply to Re: Background process
in thread Background process

Wowzers. I hadn't seen that before and finding the documentation for it took Google's help: perlport.

As an optimization, may not call the command shell specified in $ENV{PERL5SHELL}. system(1, @args) spawns an external process and immediately returns its process designator, without waiting for it to terminate. Return value may be used subsequently in wait or waitpid. Failure to spawn() a subprocess is indicated by setting $? to "255 << 8". $? is set in a way compatible with Unix (i.e. the exitstatus of the subprocess is obtained by "$?>> 8", as described in the documentation). (Win32)

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Re^3: Background process
by BrowserUk (Patriarch) on Jan 11, 2011 at 19:15 UTC

    Yes. It is very useful. I'm surprised that no one has thought to back port this to *nix.

    The only fly in the ointment is that it truncates the potentially 32-bit return value from the executable to 8-bits.

    Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
    "Science is about questioning the status quo. Questioning authority".
    In the absence of evidence, opinion is indistinguishable from prejudice.
[reply]
      Silly example, but might help. 
      #! perl -slw
use POSIX qw(:errno_h :sys_wait_h);

use constant {
  RET_SUCCESS => 1,
  RET_FAILURE => 0,
};

sub check_process_signal {
  my $sig = shift;
  if ( WIFEXITED($sig) ) {
    print q{process normal exit};
    return RET_SUCCESS;
  } elsif ( WIFSIGNALED($sig) ) {
    print q{process terminated because of signal};
    return RET_FAILURE;
  }  elsif ( WIFSTOPPED($sig) ) {
    print q{process is stopped};
    return RET_FAILURE;
  }
  return RET_SUCCESS;
}

my $pid = #run your command however....

waitpid( $pid, 0 );
if ( check_process_signal( $? ) ) {
  ## success...
} else {
  ## failure ...
}

      [download]

      Coded on the fly sorry if there are any errors.

      --Poet
[reply]
[d/l]

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