Problem with forking Post: 302309084

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Top Forums Shell Programming and Scripting Problem with forking Post 302309084 by sandy1028 on Tuesday 21st of April 2009 04:49:14 AM

04-21-2009

Registered User

Problem with forking

Hi,

Code:

my $log = IO::File->new(">$log_file_name");
$log->print("date()."--\n\n\n");
sub process {
  my ($sub_dir, $file, $config, $log) = @_;
  $log->print("-- Reading $file file\n");
}

Code:

 my $pm = new Parallel::ForkManager($tc+1);
    $pm->run_on_finish( sub { my ($pid, $exit_code, $ident) = @_; $tmpFiles[$ident] = undef; } );
 foreach my $i (0..$#tmp) {
      # Forks and returns the pid for the child:
      my $pid = $pm->start($i) and next;
      $SIG{INT} = 'DEFAULT';
      my $filename = $tmp[$i]->filename();
      my $file = IO::File->new("<$filename") or die "Can't open $filename\n";
      while((my $line) = $file->getline()) {
        last unless defined($line);
        chomp $line;
        my ($dir, $file) = split(/\t/, $line);
        #  my $process = shift; is created above 
# Calling this from another file
        $process->($dir, $file, $config, $log);
      }
      $pm->finish; # Terminates the child process
    }

Here 5 process is created and subroutine is called from another file which opens a log file write. <br>
$process->($dir, $file, $config, $log);
The problem is while writing to the file some of the data is missed out because it is not synchronized.

How can I synchronize all the forked process to write to same log file or create a different log file for each.
or How can I create a threading process as the replacement for forking process

Thanks in advance.

sandy1028

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LEARN ABOUT SUSE

mlm

FBB::mlm(3bobcat)                                             OFoldStream manipulator                                            FBB::mlm(3bobcat)

NAME

       FBB::mlm - Manipulator modifying left margins of OFoldStream objects

SYNOPSIS

       #include <bobcat/ofoldstream> or
       #include <bobcat/ofoldstreambuf>
       Linking option: -lbobcat

DESCRIPTION

       The  mlm  class  implements  a  manipulator that can be inserted into OFoldStream objects to modify the stream's left margin by a requested
       amount. The request cannot result in a negative left margin value. If a negative left margin would be the arithmetic result of the  request
       then left margin 0 will silently be used.

       Depending  on  the  tab-setting  of  the  OFoldStream  the  inserted value represents the number of blank space characters or the number of
       tab-characters that will be added to the left margin.

       The request will be processed at the next newline character or std::flush or std::endl manipulator that is inserted into the stream.  If  a
       line  is  still empty once an mlm object and a flush manipulator are inserted into the stream then the new left margin will be effective at
       the next word inserted into that line (cf., the example section below)

       A bad_cast exception is thrown when the manipulator is inserted into an ostream that is not using a OFoldStreambuf buffer.

NAMESPACE

       FBB
       All constructors, members, operators and manipulators, mentioned in this man-page, are defined in the namespace FBB.

INHERITS FROM

       -

CONSTRUCTOR

       o      mlm(int addValue):
              The standard copy constructor is available.

MEMBER FUNCTIONS

       There are no public or protected member functions in this class.

EXAMPLE

           #include <iostream>
           #include <bobcat/ofoldstream>

           using namespace std;
           using namespace FBB;

           int main()
           {
               OFoldStream out(cout, 0, 80);
               out << "hello world (left margin is 0)" << mlm(4) << "
"
                      "this uses a 4 character wide left margin
" <<
                       mlm(-10) << flush <<
                       "left margin -6 changed to 0, active on this line
";
               return 0;
           }

FILES

       bobcat/mlm - defines the class interface

SEE ALSO

       bobcat(7), manipulators(3bobcat), lm(3bobcat), ofoldstream(3bobcat)

BUGS

       None Reported.

DISTRIBUTION FILES

       o      bobcat_3.01.00-x.dsc: detached signature;

       o      bobcat_3.01.00-x.tar.gz: source archive;

       o      bobcat_3.01.00-x_i386.changes: change log;

       o      libbobcat1_3.01.00-x_*.deb: debian package holding the libraries;

       o      libbobcat1-dev_3.01.00-x_*.deb: debian package holding the libraries, headers and manual pages;

       o      http://sourceforge.net/projects/bobcat: public archive location;

BOBCAT

       Bobcat is an acronym of `Brokken's Own Base Classes And Templates'.

COPYRIGHT

       This is free software, distributed under the terms of the GNU General Public License (GPL).

AUTHOR

       Frank B. Brokken (f.b.brokken@rug.nl).

libbobcat1-dev_3.01.00-x.tar.gz                                      2005-2012                                                   FBB::mlm(3bobcat)