03-26-2006
Fork() system call time?
One more question. How can i calculate the time that system needs to make fork() system call? I need to make it with
times function but i really don't know how.
10 More Discussions You Might Find Interesting
1. UNIX for Advanced & Expert Users
I desperately wanted one of the UNIX Gurus to help me resolve my problem asap(I have to deliver the code to the client by Monday 08-oct).
I have a file with around 5 million records (50 lakhs). Now my original process was taking around 30 hours to read the complete file, process each and every... (4 Replies)
Discussion started by: kkumar1975
4 Replies
2. Programming
Can anyone please help me in measuring the system call timings!
How do I do it if I have to measure the timing of an operation, say getpid system call.
What different functions can I use for that and what would be the difference using each of them?
Thanx! (3 Replies)
Discussion started by: chacha
3 Replies
3. UNIX for Dummies Questions & Answers
Can anyone explain me what really happens when a system call fork() is called ?
I like to know what happens internally.
Thanks in Advance.
- Arun (1 Reply)
Discussion started by: arunviswanath
1 Replies
4. UNIX for Dummies Questions & Answers
Hi folks,
I want to know how this below program works?
#include <stdio.h>
int main()
{
printf("A\n");
fork();
printf("B\n");
fork();
fork();
printf("D\n");
fork();
printf("C\n");
}
This is just for example. How this type of programs where fork is used many places, how the... (1 Reply)
Discussion started by: u_peerless
1 Replies
5. Homework & Coursework Questions
Use and complete the template provided. The entire template must be completed. If you don't, your post may be deleted!
1. The problem statement, all variables and given/known data:
i have a problem in understanding the behaviour of fork .
i understood fork as to create a new process and... (4 Replies)
Discussion started by: MrUser
4 Replies
6. Shell Programming and Scripting
hi,
i tried the following source codes:
fork1.c:
main()
{
printf("demo of fork\n");
fork();
printf("hello");
}
output:
demo of fork
hello hello
fork2.c:
main()
{
printf("demo of fork"); (0 Replies)
Discussion started by: pnirmala
0 Replies
7. Programming
hi all,
i tried the following source codes:
fork1.c:
main()
{
printf("demo of fork\n");
fork();
printf("hello");
}
output:
demo of fork
hello hello
fork2.c:
main() (3 Replies)
Discussion started by: pnirmala
3 Replies
8. UNIX for Advanced & Expert Users
Hi
I wrote a simple fork program to illustrate the fork() system cal. here it is
#include<stdio.h>
#include<sys/stat.h>
#include<sys/types.h>
main()
{
int flag;
flag=fork();
if(flag==0)
{
printf("Child \n");
printf("Process id= %d\n",getpid());
... (3 Replies)
Discussion started by: badsha6642
3 Replies
9. Shell Programming and Scripting
Hi, I'm writing a shell script where I want to call fork(). However I wrote like this "var=fork()" in c style and got this error:
"syntax error near unexpected token `(' "
How could I call fork() in shell script? Thanks in advance.
Duplicate Post - Continue Here - Please Do Not Cross Post... (0 Replies)
Discussion started by: Xiaoya
0 Replies
10. Ubuntu
Hi, I'm writing a shell script where I want to call fork(). However I wrote like this "var=fork()" in c style and got this error:
"syntax error near unexpected token `(' "
How could I call fork() in shell script? Thanks in advance. (2 Replies)
Discussion started by: Xiaoya
2 Replies
LEARN ABOUT FREEBSD
vfork
VFORK(2) BSD System Calls Manual VFORK(2)
NAME
vfork -- create a new process without copying the address space
LIBRARY
Standard C Library (libc, -lc)
SYNOPSIS
#include <unistd.h>
pid_t
vfork(void);
DESCRIPTION
The vfork() system call 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(2). The vfork() system call differs from fork(2) 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.
The vfork() system call returns 0 in the child's context and (later) the pid of the child in the parent's context.
The vfork() system call can normally be used just like fork(2). It does not work, however, to return while running in the child's 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(2) rather than exit(3) if you cannot execve(2), since exit(3) will flush and close standard I/O channels, and
thereby mess up the parent processes standard I/O data structures. (Even with fork(2) it is wrong to call exit(3) since buffered data would
then be flushed twice.)
RETURN VALUES
Same as for fork(2).
SEE ALSO
_exit(2), execve(2), fork(2), rfork(2), sigaction(2), wait(2), exit(3)
HISTORY
The vfork() system call appeared in 2.9BSD.
BUGS
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 ioctl(2) calls are allowed and input attempts result in an end-of-file indication.
BSD
November 13, 2009 BSD