My question is, how do you fork only the parent processes in unix? For example how would I use the fork function to fork the parent process more than once and leave the children processes alone.
That's what fork()'s return value is for. children will know they are children.
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 BSD
vfork
VFORK(2) System Calls Manual VFORK(2)NAME
vfork - spawn new process in a virtual memory efficient way
SYNOPSIS
pid = vfork()
int pid;
DESCRIPTION
Vfork can be used to create new processes without fully copying the address space of the old process, which is horrendously inefficient in
a paged environment. It is useful when the purpose of fork(2) would have been to create a new system context for an execve. Vfork differs
from fork in that the child borrows the parent's memory and thread of control until a call to execve(2) or an exit (either by a call to
exit(2) or abnormally.) The parent process is suspended while the child is using its resources.
Vfork returns 0 in the child's context and (later) the pid of the child in the parent's context.
Vfork can normally be used just like fork. It does not work, however, to return while running in the childs context from the procedure
that called vfork since the eventual return from vfork would then return to a no longer existent stack frame. Be careful, also, to call
_exit rather than exit if you can't execve, since exit will flush and close standard I/O channels, and thereby mess up the parent processes
standard I/O data structures. (Even with fork it is wrong to call exit since buffered data would then be flushed twice.)
SEE ALSO fork(2), execve(2), sigvec(2), wait(2),
DIAGNOSTICS
Same as for fork.
BUGS
This system call will be eliminated when proper system sharing mechanisms are implemented. Users should not depend on the memory sharing
semantics of vfork as it will, in that case, be made synonymous to fork.
To avoid a possible deadlock situation, processes that are children in the middle of a vfork are never sent SIGTTOU or SIGTTIN signals;
rather, output or ioctls are allowed and input attempts result in an end-of-file indication.
4th Berkeley Distribution June 30, 1985 VFORK(2)