fork with gcc on windows
I am using fork in my program on windows using gcc (cygwin). It runs fine on my system. but I want to run on other systems which dont have cygwin. How can I do that? ...
fork
C - How to locate temp files previously created by tmpfile() ?
I'm working on a multi-process program which basically perform fuzzification on each layer of a RVB file. (1 process -> 1 layer). Each child process is delivering a temp file by using the function: tmpfile(). After each child process finishes its job, the main process has to read each temp file created and assemble the data. The problem ...
why only my first x forks make the job (gcc)
before you ask... this is from my study guide. From my perspective this is almost done but I can't put it working in the way I want. the exercise is: given an string fork X times and print one character per child until the the string finish. this is the code and compiles: #include <stdio.h> #include <unistd.h> #include <stdlib.h> #inc...
Why doesn't my parent process wait for its child to finish executing?
I have the most basic script: $pid = pcntl_fork(); if ($pid == -1) { die('could not fork'); } else if ($pid) { // we are the parent echo "parent done"; pcntl_wait($status); //Protect against Zombie children echo "all done"; } else { // we are the child echo "Child finished"; } When I run this, the ou...
Waiting for all child processes before parent resumes execution UNIX
In my program I am forking (in parallel) child processes in a finite while loop and doing exec on each of them. I want the parent process to resume execution (the point after this while loop ) only after all children have terminated. How should I do that? i have tried several approaches. In one approach, I made parent pause after while ...
How to "fork" a video conversion process into background, in php?
I have a batch flash upload script, that uploads video files to a dir. Simple. After the upload completes, it creates a mysql record for that file, and moves on to the next file in the queue. Just before it does that, I want it invoke a background process that will convert the uploaded avi avi file to an ipod compatible mp4 file, as wel...
What systems do not support WNOHANG option for waitpid?
I have a library for managing child processes that relies on passing the POSIX WNOHANG option to waitpid to perform a non-blocking wait on a process. It is said that not all systems support this option, but it has been a while since I have worked on any of those systems. What systems don't support this option? I'd like to know so that ei...
How can Perl share global variables in parallel processing?
use Parallel::ForkManager; use LWP::Simple; my $pm=new Parallel::ForkManager(10); our $a =0; @LINK=( 10,203, 20, 20 ,20 ,10 ,101 ,01 ,10 ) ; for my $link (@LINK) { $pm->start and next; my $lo = ($link * 120.22 )*12121.2121212121212121*( 12121212.1212121+ $link); $a = $a+ $lo ; print $a."\n" ; $pm->finis...
Get the child PID after system()
Hi, As far as I understand, the system() call uses internally fork() and exec() but encapsulates them for a easier handling. Is it possible to get the PID from the child process created with the system() call? Aim: I want to be able to SIGINT any child process after a certain timeout. I could rebuild the system() function by using fo...
Forking a gem for a Rails project
I've found myself twice in this situation: I install a gem on my system and start using it from my Rails project. Eventually I need to make some changes to that gem. How should I proceed? Ideally I'd like to check out the source code of that gem somewhere, like ~/third_party/gems, work on it and have my Rails project use that instead. I...
How to handle execvp(...) errors after fork()?
I do the regular thing: fork() execvp(cmd, ) in child If execvp fails because no cmd is found, how can I notice this error in parent process? ...
How to wait for process child?
I do the usual fork + exec combination: int sockets [2]; socketpair (AF_LOCAL, SOCK_STREAM, 0, sockets); int pid = fork (); if (pid == 0) { // child dup2 (sockets[0], STDIN_FILENO); dup2 (sockets[0], STDOUT_FILENO); execvp (argv[0], argv); _exit (123); } // parent close (sockets[0]); // TODO wait and see if child crashes I...
C++ fork() and execv() problems
Hi all, I am kind of newbie on C++, and working on a simple program on Linux which is supposed to invoke another program in the same directory and get the output of the invoked program without showing output of the invoked program on console. This is the code snippet that I am working on: pid_t pid; cout<<"General sentance:"<<en...
Using Unix Process Controll Methods in Ruby
Ryan Tomayko touched off quite a fire storm with this post about using Unix process control commands. We should be doing more of this. A lot more of this. I'm talking about fork(2), execve(2), pipe(2), socketpair(2), select(2), kill(2), sigaction(2), and so on and so forth. These are our friends. They want so badly just to help us. ...
How to install third appliacations to iphone(has been jailbreaked) via shell script
Anybody can tell me how to install a third app to iphone? I want to use shell script,but I can't use fork(),Anybody has an idea? ...
[APUE]Does parent and child share the same file offset after fork?
In APUE section 8.3 fork function, about file sharing between parent and child processes, It said: It is important that the parent and the child share the same file offset. And in section 8.9 Race Conditions, there is a example: both parent and child write to a file which is opened before invoking fork function. The program contains a...
gdb detaching after fork from child process - disable?
Getting this message inside gdb. I know its not an error or anything. I also did pagination so thats not an issue. Is there any way to suppress this message? ...
how to set close-on-exec by default
I'm implementing a library to run commands. The library is C, on Linux. It currently does a popen() call to run a command and get output. The problem is that the command inherits all currently open file handlers. If I did a fork/exec I could close the handlers in child explicitly. But that means re-implementing popen(). Can I set clos...
Is it possible using Linux's clone() system call to run multiple applications in the same address space?
If you don't pass the CLONE_VM flag to clone(), then the new process shares memory with the original. Can this be used to make two distinct applications (two main()'s) run in the same process? Ideally this would be as simple as calling clone() with CLONE_VM and then calling exec(), but I realize it's probably more involved. At the very l...
exec and fork()
What are the differences between fork() and exec()? ...