fork

问题 I'm trying to make a program which make 9 child process, so I use fork 9 times only if we are the father, like this: for (int i = 0; i < 9; i++) { // Creo 9 hijos. if (child_pid > 0) { child_pid = fork(); childs[i] = child_pid; } if (child_pid < 0) printf("Error...\n"); } Now, I have to print on each children what children he is, starting from 0, so I was thinking about this: printf("This is child #%d\n", getpid() - getppid()); But I'm not sure, Does this always work?, What if while the

问题 Problem: Call/Initialize Poco code from inside a C library, using loader (3rd party C program, our code is in c++). The Program loads our library, our lib initializes Poco::Logger and uses AsyncChannel + FileChannel in the logger. Fork from this process. Run some threads in the child process. try to exit the child process, joining threads. The AsyncChannel's destructor blocks on close(), essentially polling Queue and sleeping. The _queue has 1 element always when the destructor for

问题 I need to have functionality that would essentially emulate user creating a port forwrding with ssh. So, essentially that should work like that: - execute ssh -f -N -L 10000:gateway:11000 localhost - if there is an output from that command, show to the user and pump user's input as a response - finish The code I came up with below, almost does what I need: ssh_proc = Popen(['ssh', '-f', '-N', '-L', '10000:gateway:11000', 'localhost'], stdin=PIPE, stdout=PIPE) stdoutdata, stderrdata = ssh_proc

问题 I am trying to run a new process in background so it will be possible to continue working with parent process. I used fork then execl. I tried to add to the execl command the argument & but it doesn't work: execl("newproc","newproc","arg1","&",NULL); Is there any solution? 回答1: The problem is that & is not a command line option to programs. Instead, it is merely special shell syntax which puts a command in the background. The distinguishing feature of background programs is that they are not

问题 I am making a connect four game and I would like to have Multiple processes and pipes, but I'm not sure where to start. I know you have to use fork and pipe, but when I fork just before the start of the game I get the same result for each game. I'm just confused where to go from here. Any suggestion would be greatly appreciated. Below is some of my code, I remover the parts for checking for wins, because I is not necessary to see. #include <stdio.h> #include <stdlib.h> #include <unistd.h>

问题 I'm new to socketpairs and I need my children each to pass information from a structure to the parent.I was told this can be done using SOCK_DGRAM but I don't know how to do it.I looked over the internet but i couldn't find a concrete example.Can you please show for example hoe can you pass to the parent a structure made out of 2 ints and a string maybe ?I just want an example so I can understand how I could build this kind of socketpair and send information through it.Thank you 回答1: How

问题 How can I add a counter in my code in order to be able to count the position of each process. Right now I'm getting the following output: Process Pid: 6179 PPid: 4378 (position: ?). Process Pid: 6181 PPid: 6179 (position: ?). Process Pid: 6180 PPid: 6179 (position: ?). Process Pid: 6185 PPid: 6180 (position: ?). Process Pid: 6183 PPid: 6181 (position: ?). Process Pid: 6182 PPid: 6181 (position: ?). Process Pid: 6184 PPid: 6180 (position: ?). All I want is to be able to output the Pid position

问题 Note: For simplicity, I don't include much error checking and my sample code doesn't really serve any practical purpose. What I want: I want a program that fork() s a child process and has it invoke a process using execl() . My parent then retrieves the exit code for that process. This is fairly trivial. What I tried: int main(int argc, char** argv) { int ch = fork(); if(ch == -1) { perror(NULL); }else if(ch == 0) { // In child, invoke process execl("/path/process", "process", 0); }else { //

问题 ANSWER in this previous question: https://stackoverflow.com/a/2035683/960086 It was not checked and quiet down, so I missed it. Already asked to be posted here I am playing around with an application that creates a socket connection on a child process. Now my problem is that trying to test it, but every time I run the application Netbeans creates main(Build, Run) and main(Run) when I close by clicking the red square or bottom right main(run) X button. The process "terminate" but it stays

问题 I have a global variable, X. I then fork and modify X from the child. I want those changes to show up in the parent, but I don't want the parent to have to wait on the child. How can I do this? 回答1: You need to put the variable in shared memory. There are many ways to create shared memory. I'd probably just use mmap , but you could also check out shmget or shm_open . 回答2: When you fork a new process that is a separate copy of the address space. It can only see the changes made before the fork