fork | 易学教程

Forking a fork of my repo in GitHub

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问题 I have a repo on GitHub. Someone forked that repo and is doing some work in their fork. I want to fork their fork to help them before they do a pull request to get the repo back into the main repo which I own. Problem is that when I try and fork their for (of my repo) it won't allow me to fork that back into my "area." What is the paradigm that's typically followed to achieve what I'm trying to do above? 回答1: I would recommend making a new branch off the branch you are both collaborating on,

Forking a fork of my repo in GitHub

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In fork() which will run first, parent or child?

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问题 When the following code runs, I understand the parent and child both will run in parallel immediately after fork() is called. #include <stdio.h> #include <stdlib.h> #include <errno.h> #include <sys/types.h> #include <unistd.h> int main(void) { int pfds[2]; char buf[30]; pipe(pfds); if (!fork()) { printf(" CHILD: writing to the pipe\n"); write(pfds[1], "test", 5); printf(" CHILD: exiting\n"); exit(0); } else { printf("PARENT: reading from pipe\n"); read(pfds[0], buf, 5); printf("PARENT: read \

Will os.fork() use copy on write or do a full copy of the parent-process in Python?

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问题 I would like to load a rather large data structure into a process and then fork in the hope to reduce total memory consumption. Will os.fork work that way or copy all of the parent process in Linux (RHEL)? 回答1: Even if COW is employed, CPython uses reference counting and stores the reference count in each object's header. So unless you don't do anything with that data, you'll quickly have spurious writes to the memory in question, which will force the system to copy the data. Pass it to a

Porting an application with fork() to pthread_create()

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问题 I am porting a linux application to the iphone and I would like to know how much re-writing I have to do to make it a multi-threaded application rather than a multi-process application. Also, if I simply replace the forked code with a call to the functions on another thread I get exec_bad_address at seemingly random places in my flow of execution... Does anyone know why this may be the case? Thanks! 回答1: It is exactly the same effort you would undergo in transitioning your application to a

fork(), problems with multiple children

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问题 I edited a little bit : for ( ii = 0; ii < nbEnfants; ++ii) { switch (fork()){ case -1 : { printf("\n\nSoucis avec fork() !!! \n\n"); exit(0); }; case 0 : { EEcrireMp(ii); }break; default : { tabPidEnfants[ii] = p; usleep(50000); ELireMp(nbSect, nbEnfants,tabPidEnfants); }; } } My problem : i get to many child, like a bomb of children spawning. How can i stop those child ? the break should stop it no ? Thanks 回答1: So, when you fork a process, the new process is an identical copy of the parent

About fork system call and global variables

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问题 I have this program in C++ that forks two new processes: #include <pthread.h> #include <iostream> #include <unistd.h> #include <sys/types.h> #include <sys/wait.h> #include <cstdlib> using namespace std; int shared; void func(){ extern int shared; for (int i=0; i<10;i++) shared++; cout<<"Process "<<getpid()<<", shared " <<shared<<", &shared " <<&shared<<endl; } int main(){ extern int shared; pid_t p1,p2; int status; shared=0; if ((p1=fork())==0) {func();exit(0);}; if ((p2=fork())==0) {func()

Display number of processes in loop with fork

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问题 How can I display the number of processes created? (without using a formula) for (i=0; i<3; i++) fork(); count = count + 1; printf("%d",count); 回答1: There are a number of ways to do this, and a good technique is to have each child write one byte into a file descriptor which the original process can read. Note that, for the sake of brevity, the following code contains absolutely no error checking. Also, we report only the number of spawned processes (7) rather than counting the original to get

Fork() on iPhone

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问题 Does the the iPhone SDK allow fork() and pipe() , the traditional unix functions? I can't seem to make them work. Edit Problem solved. Here, I offer a solution to anybody who encounters problems similar to me. I was inspired by the answers in this thread. In iPhone, there is no way to fork a process. However, it's not impossible to implement piping. In my project, I create a new POSIX thread (read Apple's documentation for how to do this). The child thread would share a file descriptor

Socket网络编程--Libev库学习(3)

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　　这一小节继续讲解各个观察器(Watcher). 　　上一小节已经讲解了ev_io(IO可读可写观察器)，ev_stat(文件属性变化观察器)，ev_signal(信号处理观察器)，ev_timer(定时器)，ev_periodic(周期任务处理)，ev_child(子进程状态变化观察器)。这一小节准备讲ev_fork(创建的进程时的观察器)，ev_async(异步调用观察器)，ev_cleanup(event loop退出时触发事件)，ev_prepare(每次event loop之前事件),ev_check(每次event loop之后事件)，ev_idle(每次event loop空闲触发事件). 　　ev_async (ev_async当ev_async_send通过watcher调用时调用，触发EV_ASYNC) 1 #include <stdio.h> 2 #include <string.h> 3 #include <unistd.h> 4 #include <stdlib.h> 5 #include <ev.h> 6 7 ev_async async_watcher; 8 9 static void sigint_callback(struct ev_loop *loop,ev_signal * w,int revents) 10 { 11 if(revents