Comments on: Understanding Linux InterProcess Communication-III: Duplicate Process

By: amritpreet singh

amritpreet singh — Sat, 05 Jan 2013 15:51:32 +0000

studied and implemented
# all questions on signal handlers using signal().
# signal handler using sigaction().
# retrieval of the siginfo.

By: samta

samta — Sat, 05 Jan 2013 08:40:13 +0000

Implemented
#Todays assignment questions on signal system calls and sigaction
#Obtained the signal info using signal structure

By: samta

samta — Fri, 04 Jan 2013 10:54:18 +0000

**Resolved the issue faced above in earlier assignment by assuming any process can function first child or parent

Implemented
#All the 4 exec functions
#using the file descriptor frm 1 process into another replaced process
#called fork() function in the child process and kept the parent process and the new replaced process printg their data

**Issues faced
1)All the printf commands above fork() or exec() were nt printg the data in the output
Resolved this by putting \n at the end of every printf statement. as without \n at the end it was taking data in the stdout buffer but was nt printg it.

2)execlp and execvp were nt executing
as in it one has to put the name of the file twice and nt once

By: amritpreet singh

amritpreet singh — Thu, 03 Jan 2013 11:43:59 +0000

happened with me too………added a loop before return statement to stop the prior termination of the parent process.
if(pid)
{ for(i=0;i<20;i++)
printf("i m the parent process");
}
but dont know the reason

By: amritpreet singh

amritpreet singh — Thu, 03 Jan 2013 11:39:28 +0000

studied and implemented
#all assignment questions of first session(i.e. system(),fork(),wait())
#all assignment questions of second session.(all exec commands )
#performed passing file-descriptor from one process to another process & displayed its file contents.

By: samta

samta — Wed, 02 Jan 2013 13:33:55 +0000

Implemented:::
#All the IPC classroom questions on processes..

**Issues
void main()
{
pid_t pid;
pid=fork();
pid=fork();
if(pid==0)
printf(“\nIn child process PID=%d and PPID=%d”,getpid(),getppid());
else if(pid>0)
printf(“\nIn parent process PID=%d and PPID=%d”,getpid(),getppid());
else
printf(“\nHere is an error!!!”);
}

The similar code which I saw in the lecture today did run properly and the shell didnt hang while in my code both the parent processes are terminating first and then the orphan processes are hanging the shell…