unnamed pipes and threads Post: 302573797

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Top Forums Programming unnamed pipes and threads Post 302573797 by nimesh on Tuesday 15th of November 2011 03:17:10 PM

11-15-2011

Registered User

unnamed pipes and threads

Hi!
I am writing a C program that will create a child, child will create a thread and the thread will send a message to a unnamed pipe and will print the message before exiting.

here is my work:

Code:

#include <sys/types.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <pthread.h>
#include <string.h>
 
void *thread_function (void *arg);
char message [] = "Hello World";
int fd[2]; // Creating file descriptor
char buff [100];
 
int main()
{
  pipe (fd); //creating unnamed pipe
  pid_t pid;
  pthread_t a_thread;
  void *thread_result;
  pid = fork();
  switch(pid)
  {
    case -1:
      perror("fork failed");
      exit(1);
    case 0: // creating child
      printf("Child Running\n");
      pthread_create (&a_thread, NULL, thread_function, (void *)message);
      sleep (3);
    default:
      break;
  }
  close (fd[1]); //closing write file descriptor
  close (fd[0]); //closing read file descriptor
  exit(0);
}
 
 
void *thread_function (void *arg)
{
  printf ("Thread running\n");
  sleep (3);
  write (fd[1], message, strlen (message)); // writing to pipe
  read (fd[0], buff, strlen (message)); // reading from file
  printf ("Message is: %s\n", buff);
  pthread_exit("thread exiting");
}

Seems like my thread doesn't exit and also the message is not send to pipe in thread

thank you

Last edited by Scott; 11-15-2011 at 04:29 PM.. Reason: Please use code tags... and indent your code. Thanks.

nimesh

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LEARN ABOUT HPUX

create_child

create child(1m)														  create child(1m)

NAME

       create child - Creates a child pointer at the master replica of the parent directory

SYNOPSIS

       cdscp create child child-name clearinghouse clearinghouse-name

ARGUMENTS

       The full name of the child pointer.  The full name of a clearinghouse that contains a replica of the child directory.

DESCRIPTION

       The create child command creates a child pointer at the master replica of the parent directory.	When CDS looks up a name in the namespace,
       it uses child pointers to locate directory replicas.  Use the set cdscp preferred clearinghouse command	before	issuing  this  command	to
       ensure that the request is directed to the master replica.

   Privilege Required
       You must have insert permission to the parent directory.

NOTES

       Use  the  create  child	command  only  to  re-create a child pointer that is accidentally deleted. This command is designed only for trou-
       bleshooting.

       This command will fail if the associated directory does not exist.  If the associated directory exists, this command will  return  success-
       fully.

       This command is replaced at Revision 1.1 by the dcecp command and may not be provided in future releases of DCE.

EXAMPLE

       The  following  command	creates the child pointer in the parent directory /.:/subsys.  It uses the replica located at the /.:/subsys/NY_CH
       clearinghouse to fill in its replica set.

       cdscp> create child /.:/subsys clearinghouse /.:/subsys/NY_CH

RELATED INFORMATION

       Commands: delete child(1m), list child(1m), show child(1m)

																  create child(1m)

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