I made the following programs in Perl before: my $db = DBconnection with DB2 if ($pid = fork()) { #parent } else { #child $db->execute("SELECT ****"); exit; } wait(); $db->execute("SELECT ****"); I thought that it waited for the end of the child process to have wanted to do it and would operate it for DB by a pro-pro...
hi, can someone help me about how to create multiple child processes which have the same parent in order to do "some" part of particular job? for example, an external sorting algorithm which is applied with child processes; each child process sorts a part of data and finally the parent merges them.. EDIT: Maybe I should mention the f...
hi, referring to my last question (http://stackoverflow.com/questions/876605/multiple-child-process), i am now trying to make an external sorting implementation using multiple child process. ... fp = fopen(pathname, "r"); // open inputfile in r mode fgets(trash, 10, fp); // ignore first line for (i=0; i<numberOfProcess; ++i) { #ifdef...
In my simple custom shell I'm reading commands from the standard input and execute them with execvp(). Before this, I create a fork of the current process and I call the execvp() in that child process, right after that, I call exit(0). Something like this: pid = fork(); if(pid == -1) { perror("fork"); exit(1); } if(pid == 0) ...
On most UNIX systems passing an open file between processes can be easily done for child/parent processes by fork(); however I need to share a fd "after" the child was already forked. I've found some webpages telling me that sendmsg() may work for arbitary processes; but that seems very OS dependent and complex. The portlisten seems lik...
Here's my code: #include <stdio.h> #include <stdlib.h> #include <unistd.h> #include <wait.h> #include <readline/readline.h> #define NUMPIPES 2 int main(int argc, char *argv[]) { char *bBuffer, *sPtr, *aPtr = NULL, *pipeComms[NUMPIPES], *cmdArgs[10]; int fdPipe[2], pCount, aCount, i, status, lPids[NUMPIPES]; pid_t pid; ...
Two C executables A and B exist. A and B communicate to each other through a socket. B can be started independently or through A. If B is started first and A is started next, then A and B start properly without issues. Even if A is restarted, then there are no issues. If B is started through A, then A and B starts properly. But here ...
I have been trying to write a bare-bones ping scanner using Perl for internal use. Since it scans a 24-bit CIDR network the script takes too long to run if it runs in a single thread. I have tried adding fork functionality to speed up the process but my first attempt was taking pretty much the same time since there was only one child pro...
I've created a question about this a few days. My solution is something in the lines of what was suggested in the accepted answer. However, a friend of mine came up with the following solution: Please note that the code has been updated a few times (check the edit revisions) to reflect the suggestions in the answers below. If you intend...
I am writing a Bulk Mail scheduler controlled from a Perl/CGI Application and would like to learn abut "good" ways to fork a CGI program to run a separate task? Should one do it at all? Or is it better to suffer the overhead of running a separate job-queue engine like Gearman or TheSchwartz as has been suggested recently. Does the answer...
Say, i need to run a bunch of code that is prone to crash so i need to run it on a different process. Typically i'd do it something like this: pid = fork(); if (pid == -1) { std::cout << "Cant Spawn New Thread"; exit(0); } else if (pid == 0) { std::cout << "Im a child that will crash\n"; char *foo = (char *) 0xffff...
In many programs and man pages of Linux, I have seen code using fork(). Why do we need to use fork() and what is its purpose? ...
I guess the question says it all. I want to fork on windows. What is the most similar operation and how do I use it. ...
Hi, The following code segment takes more time (5s) when it is run first time and takes less time(250ms) on consecutive runs. Is there any better way to execute gcc. int pid,status; char * argv[] = {"gcc","program.c",NULL}; if(!(pid=fork())){ execvp("gcc",argv); } while(pid!=wait(&status)){ //do nothing } ...
On a linux system, does the child process view the existing threads the same way as the parent process ? int main() { //create thread 1 . . . int child_pid = fork(); if ( 0 == child_pid) { .. } else { .. } Since the whole address space is copied for the child process, what happens to the state of the threads. What if the thread 1 in...
If I setup sighandler and then do a fork. Will the child process also inherit the sighandlers? ...
Hello, I am attempting to programmatically track the processes a linux user is currently running. Is it possible to be notified when a user has fork-ed or exec-ed a new process, or is the only solution to perpetually poll the process list for new processes. Thanks, Ken ...
Hi all, I have a problem, I use pcntl_fork to fork a process in PHP, $pid = pcntl_fork(); if ($pid == -1) { die('could not fork'); } else if ($pid) { // we are the parent pcntl_wait($status); //Protect against Zombie children } else { pcntl_exec("/path/to/php/script"); echo "Could not Execute..."; } I am trying to figure out a w...
I am wanting to use ffmpeg to convert video to .flv in php. Currently I have this working, but it hangs the browser until the file is uploaded and is finished. I have been looking at the php docs on how to run an exec() process in the background, while updating the process using the returned PID. Here is what I found: //Run linux com...
I've heard that mixing forking and threading in a program could be very problematic, often resulting with mysterious behavior, especially when dealing with shared resources, such as locks, pipes, file descriptors. But I never fully understand what exactly the dangers are and when those could happen. It would be great if someone with expe...