02-27-2002
10 More Discussions You Might Find Interesting
1. UNIX for Dummies Questions & Answers
What is a fork? Why would one create a fork? What are the advantages and disadvantages of using a fork?
Please advise.
Thank You.
Deepali (5 Replies)
Discussion started by: Deepali
5 Replies
2. Programming
#include <stdio.h>
#include <string.h>
#include <sys/types.h>
#define MAX_COUNT 200
#define BUF_SIZE 100
void main(void)
{
pid_t pid;
int i;
char buf;
fork();
pid = getpid();
for (i = 1; i <= MAX_COUNT; i++) {
sprintf(buf,... (2 Replies)
Discussion started by: MKSRaja
2 Replies
3. Programming
Hello all.
I'm developing a filetransfer application, which is supposed to work sort of like dcc, with multiple transfers etc. Now i wonder what the best way to manage the transfers is. Should i fork() for each new transfer, hogging loads of memory or use pthreads? Maybe I can use select to see... (0 Replies)
Discussion started by: crippe
0 Replies
4. Programming
hi all
About this code
for (i = 1; i < n; i++)
if ((childpid = fork()) <= 0)
break;
I really can't understand the output .
and the way fork () return the value .
how about the process Id ,the child process Id and the parent ID
in this case
so please answer me soon (5 Replies)
Discussion started by: iwbasts
5 Replies
5. Programming
Hi everybody,
I wanna write a code to understand how fork works.
my target
--------------
-Parent creates a file(called temp) and writes into this file "1".Then it closes the file.
-Then parent creates a child and wait until execution of this child ends.
-Then child opens the same... (3 Replies)
Discussion started by: alexicopax
3 Replies
6. UNIX for Advanced & Expert Users
Hi,
I wrote a simple program for understanding the fork command. The code is as below
int main(void)
{
fork(); printf("hi 1 \n");
fork(); printf("hi 2 \n");
fork(); printf("hi 3 \n");
}
I am getting a variation in the number of times the printf is called if i remove the \n from each of... (1 Reply)
Discussion started by: xyz123456
1 Replies
7. Programming
Hi,
I wrote a simple program for understanding the fork command. The code is as below
int main(void)
{
fork(); printf("hi 1 \n");
fork(); printf("hi 2 \n");
fork(); printf("hi 3 \n");
}
I am getting a variation in the number of times the printf is called if i remove the \n from each... (2 Replies)
Discussion started by: xyz123456
2 Replies
8. Programming
does fork() spawn only the parent process, what if fork() is looped, does it spawn the parent and the child? (4 Replies)
Discussion started by: Peevish
4 Replies
9. UNIX for Dummies Questions & Answers
I'm trying to run a simple test on how to use fork(), i'm able to execute the child process first then the parent, but how can I execute parent then child..?
Thanks! (1 Reply)
Discussion started by: l flipboi l
1 Replies
10. Programming
I understand that fork create a child but I need very simple example that make child useful....
I mean how will make the program faster anyone explain with code plz
using C plz (2 Replies)
Discussion started by: fwrlfo
2 Replies
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)