I usually find it convenient to give the child its own little section for it to run and then call exit() after so it doesn't run all the stuff below it. Much less clutter
Code:
if(in_the_child)
{
// runs in the child
command1();
command2();
command3();
// child quits so it doesn't run parent_stuff();
exit(0);
}
// Only the parent will run this stuff
parent_stuff();
parent_stuff();
parent_stuff();
Code:
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
int main(void)
{
pid_t pid[3];
int n;
for(n=0; n<3; n++)
{
pid[n]=fork();
if(pid[n] == 0) // if we are the child, exit immediately
{ exit(0); }
}
printf("Parent pid: %d\n", (int)getpid());
for(n=0; n<3; n++)
{
int status;
printf("Child %d pid: %d\n", n, pid[n]);
// We must wait for the child
waitpid(pid[n], &status, 0);
}
}
When I compile this C programme I get different outputs each time I run it
Please explain to me whats happening in the code if you can give me a detailed explanation. Because I am stuck with this.
#include <stdio.h>
main(){
int i = 0;
printf("I am the... (1 Reply)
When I compile this C programme I get different outputs each time I run it
Please explain to me whats happening in the code if you can give me a detailed explanation with the schedular functionality it will help a lot. Because I am stuck with this.
#include <stdio.h>
main(){... (3 Replies)
Hi everybody,
I'm having some problems wiriting a program in UNIX using the "fork" and "kill" system calls.
I have to create a C program P0, which creates 9 other processes
P1, P2, ..., P9, where P0 is the father of P1, P1 the father of P2, and so on.
All the processes contain an infinite... (0 Replies)
Hi
I'm currently working with C on UNIX (HPUX) and need to be able to fork a seperate Java process from within a running C process.
I can run the following code from the command line via a script but am having difficulty getting it to work from within the code.
I am trying to use execl. Is... (4 Replies)
#include <stdio.h>
#include <sys/types.h>
#include <unistd.h>
int main()
{
pid_t pID;
int i;
for (i = 0; i < 3; i++)
{
pID = fork ();
if (pID == 0)
{
printf ("Value of i --> %d... (2 Replies)
hi experts(novice people can stay away as it is no child's game),
i am developing a script which works like recycle bin of windows.
the problem i am facing is that when ever i am trying to delete a file which is situated in parent directory or parent's parent directory i am unable to... (1 Reply)
hi,
I want my program to fork a new process and then I want to kill the parent process. The parent program before dying will issue a SIGTERM to all its childs. Which eventually kills all Children.
I cant handle the SIGTERM at the child level.:(
What I was thinking of was the Parent... (3 Replies)
Keep in mind that I haven't done Perl scripting for a LONG time, so I'm quite rusty.
This is what I would like to do:
- using fork, create 3 or 4 processes to read 3 or 4 different text documents containing server names or IP addresses
- in each of those processes, Perl will ping each of those... (7 Replies)
Hi everyone
i am very new to linux , working on bash shell.
I am trying to solve the given problem
1. Create a process and then create children using fork
2. Check the Status of the application for successful running.
3. Kill all the process(threads) except parent and first child... (2 Replies)
I have an input file with contents like:
5785690|68690|898809
7960789|89709|789789
7669900|87865|659708
7869098|65769|347658
so on..
I need to pass this file to 10 parallely running processes (forking)so that each line is processed by a process and no line is processed twice and write the... (1 Reply)
Discussion started by: rkrish
1 Replies
LEARN ABOUT ULTRIX
vfork
vfork(2) System Calls Manual vfork(2)Name
vfork - spawn new process in a virtual memory-efficient way
Syntax
pid = vfork()
int pid;
Description
The can be used to create new processes without fully copying the address space of the old process, which is inefficient in a paged envi-
ronment. It is useful when the purpose of would have been to create a new system context for an The system call differs from in that the
child borrows the parent's memory and thread of control until a call to or an exit (either by a call to or abnormally.) The parent process
is suspended while the child is using its resources.
The system call returns a value of zero (0) in the child's context and, later, the pid of the child in the parent's context.
The system call can normally be used just like It does not work, however, to return while running in the childs context from the procedure
which called because the eventual return from would then return to a nonexistent stack frame. Be careful, also, to call _exit rather than
exit if you cannot call because exit will flush and close standard I/O channels and thereby cause problems in the parent process's standard
I/O data structures. Even with it is wrong to call exit, because buffered data would then be flushed twice.
Restrictions
To avoid a possible deadlock situation, processes which are children in the middle of a are never sent SIGTTOU or SIGTTIN signals. Rather,
output or ioctls are allowed, and input attempts result in an end-of-file indication.
Diagnostics
Same as for
See Alsoexecve(2), fork(2), sigvec(2), wait(2)vfork(2)