I created a script in perl to run programs with a timeout. If the program being executed takes longer then the timeout than the script kills this program and returns the message "TIMEOUT". The script worked quite well until I decided to redirect the output of the executed program. When the stdout and stderr are being redirected, the p...
I am currently writing my own shell program. This simple shell can just execute commands. When executing commands like vi or calc which require input from the terminal , the command is getting executed and is waiting for the input from the user. But I am unable to give any input on the screen. How should the input be handled during the...
I'm writing a shell which forks, with the parent reading the input and the child process parsing and executing it with execvp. pseudocode of main method: do{ pid = fork(); print pid; if (p<0) { error; exit; } if (p>0) { wait for child to finish; read input; } else { call function to parse input; exit; } }while condition return; ...
I have a perl script, script.pl which, when run, does a fork, the parent process outputs its pid to a file then exits while the child process outputs something to STOUT and then goes into a while loop. $pid = fork(); if ( ! defined $pid ) { die "Failed to fork."; } #Parent process elsif($pid) { if(!open (PID, ">>running_PIDs")...
My guesses were wrong, and had nothing to do with the answer. This question is no longer valid. See my answer. Sorry about this poor question. Tl;dr Version Why can't a Java process find a certain file, until another process – the process that created that file – has finished executing. Can this be worked around? Longer Version I hav...
Hi, I want to run a shell script in php, but this shell script takes a long time to execute (it has sleep in it), I don't want the web server to block when executing this script. I tried exec() and shell_exec() in php but the server stops until the shell script finishes! I thought of doing fork in the shell script itself but I don't kn...
I have the following situation (pseudocode): function f: pid = fork() if pid == 0: exec to another long-running executable (no communication needed to that process) else: return "something" f is exposed over a XmlRpc++ server. When the function is called over XML-RPC, the parent process prints "done closing...
I wish to sequentially run some c scripts that fork their own processes (in a new command line window) and give the "Press any key to continue..." when they are completed. Technically, it is a special compiler. It pops up with acommand line window and tells me whether the compile was successful or not. But that command line window for...
Hi I need to use shared memory and fork to do this: Multipling random 512x512 matrixes using 4 processes and shared memory. I know how to fork one child but How can I fork 4 processes that do 1/4 of work? Thanks ...
Hi I need to make 4 forks 1000 times. I wrote this but it runs forever: #include <stdio.h> #include <stdlib.h> #include <time.h> #include <sys/types.h> #define N 512 void chunk0(void); void chunk1(void); void chunk2(void); void chunk3(void); double get_time(void); void main(void) { int i,j,k,iterations=0; unsigned in...
I wrote this code: #include <stdio.h> #include <stdlib.h> #include <time.h> #include <sys/types.h> #include <sys/shm.h> #define N 512 void chunk0(unsigned int *s, unsigned int *a, unsigned int *b, int MID,int it); void chunk1(unsigned int *s, unsigned int *a, unsigned int *b, int MID,int it); void chunk2(unsigned int *s, unsig...
What is signal behavior in the fork. Should all signals are inherited in fork If not then which one and why? ...
I want to limit the subprocesses count to 3. Once it hits 3 i wait until one of the processes stops and then execute a new one. I'm using Kernel.fork to start the process. How do i get the number of running subprocesses? or is there a better way to do this? ...
I have a working Python script that executes an external command and calls Popen.communicate(). However when I call this script from a C process, it fails in os.waitpid() with "[Errno 10] No child processes". Why? This looks like a certain bug in Python, but I'm not using threads. The C process forks, changes its UID, GID, and calls se...
I'm writing a network app, where each Client has a Singleton ClientManager. For testing, I would like to create several clients (each in their own VM / process) without starting the program by hand n-times. The following two questions on stackoverflow already describe how-to do that: Is this really the best way to start a second JVM f...
Hi, I tried to start a background process with php, for that, I added a & at bottom on exec function but after a few days it stop working. Basically If i have file 1.php with: <?php var_dump(exec('/home/2.php > /home/2.output 2>&1 &')); And file 2.php with: <?php sleep(5); echo "Fill\n"; Running file 1.php, it return an empty st...
I already handled to start another VM in Java. See ProcessBuilder - Start another process / JVM - HowTo? For some reason, I can't manage to do the same in Scala. Here's my code object NewProcTest { def main(args :Array[String]) { println("Main") // val clazz = classOf[O3] val clazz = O4.getClass Proc.spawn(clazz, true...
This seems to be a fairly common thing to do, and I've managed to teach myself everything that I need to make it work, except that I now have a single problem, which is defying my troubleshooting. int nonBlockingPOpen(char *const argv[]){ int inpipe; pid_t pid; /* open both ends of pipe nonblockingly */ pid = fork(); ...
Hi. Got a problem that I'm facing. and it should be pretty simple. I have an app that places data into a dir "A". The data will be a series of files. I want to have a continually running server, that does a continual look at the dir, and on seeing a completed file in the dir, the server spawns/forks/creates a thread (not sure of the e...
Try the code below with: python fork.py and with: python fork.py 1 to see what it does. #!/usr/bin/env python2 import os import sys child_exit_status = 0 if len(sys.argv) > 1: child_exit_status = int(sys.argv[1]) pid = os.fork() if pid == 0: print "This is the child" if child_exit_status == 0: os.execl('/usr/bin/w...