i'm experimenting fork function and i found this code
I thought that there were 2^5 processes after running this code , but there were less processes.
Why?
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)
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)
Hello experts,
I am using fork() in my code but I am confused which output comes first child or parent?
I did the following code .My book shows parent first but my linux shows child first.Can anyone tell me why?
#include <stdio.h>
int main(){
int pid;
printf("I am original process with pid... (5 Replies)
Assume we have an application built on *nix that uses fork()...then the processes procedure is going to act as follow:
X is considered a parent process (first click on application)
Y is considered a child process of X (second click on application)
Z is considered a child process of Y (third... (6 Replies)
Hi everyone:
I'm developing a dynamic library for notifications, this library is used for a daemon that i've programmed, when something goes wrong the library should send an email to an administrator, but since sending an email is a non-vital process then it can fail (it should work as an... (4 Replies)
I writing a program that forks three times but only on the parent process. The three children processes then produces output in order. 1, 2, 3. I am confused on how to do this. I have tried multiple if and else if statements but the output does not come out right. How should I go about doing this? (1 Reply)
Hello everybody.I want to make clear that i am not going to ask from anybody to build my asignement but i have a big problem. I can't seem to find anywhere ONE good example on C about what i am trying to do:wall:.I think it is simple. All i ask is one example, even a link is fine.
So, i want to... (1 Reply)
Hi All,
I have a program for class that needs to do the following:
1. Print the directory entries from the current directory using ncurses
2. Provide a prompt next to each directory entry and allow the user to enter commands that may or may not be about the file
3. Execute those commands in... (1 Reply)
Hello... And thanks in advance for any help anyone can offer me on my question! I've been doing a lot of reading to try and find my answer... But I haven't had any luck
What I'm trying to understand is where a child process inherits global environment variables from? I understand the exec()... (2 Replies)
Discussion started by: bodisha
2 Replies
LEARN ABOUT OPENDARWIN
pthread_atfork
PTHREAD_ATFORK(3) Library Functions Manual PTHREAD_ATFORK(3)NAME
pthread_atfork - register handlers to be called at fork(2) time
SYNOPSIS
#include <pthread.h>
int pthread_atfork(void (*prepare)(void), void (*parent)(void), void (*child)(void));
DESCRIPTION
pthread_atfork registers handler functions to be called just before and just after a new process is created with fork(2). The prepare han-
dler will be called from the parent process, just before the new process is created. The parent handler will be called from the parent
process, just before fork(2) returns. The child handler will be called from the child process, just before fork(2) returns.
One or several of the three handlers prepare, parent and child can be given as NULL, meaning that no handler needs to be called at the cor-
responding point.
pthread_atfork can be called several times to install several sets of handlers. At fork(2) time, the prepare handlers are called in LIFO
order (last added with pthread_atfork, first called before fork), while the parent and child handlers are called in FIFO order (first
added, first called).
To understand the purpose of pthread_atfork, recall that fork(2) duplicates the whole memory space, including mutexes in their current
locking state, but only the calling thread: other threads are not running in the child process. The mutexes are not usable after the fork
and must be initialized with pthread_mutex_init in the child process. This is a limitation of the current implementation and might or
might not be present in future versions.
RETURN VALUE
pthread_atfork returns 0 on success and a non-zero error code on error.
ERRORS
ENOMEM insufficient memory available to register the handlers.
AUTHOR
Xavier Leroy <Xavier.Leroy@inria.fr>
SEE ALSO fork(2), pthread_mutex_lock(3), pthread_mutex_unlock(3).
LinuxThreads PTHREAD_ATFORK(3)