03-29-2004
When you write a value to a pipe, when is the value removed? Also does anyone have same code of creating pipes and assigning them to child processes?
Thanks,
FG
10 More Discussions You Might Find Interesting
1. UNIX for Dummies Questions & Answers
Dear all,
suppose that I start a process (named "father"). "father" starts in turns a process called "child" with an execv call (after a fork). In this way "father" will be notified if "chlid" crashes (SIGCHILD mechanism). The problem is:
if "father" crashes, how can I do to be recreate a... (1 Reply)
Discussion started by: npalmentieri
1 Replies
2. UNIX for Dummies Questions & Answers
I don't follow what these are...
this is what my text says...
"When a process is started, a duplicate of that process is created. This new process is called the child and the process that created it is called the parent. The child process then replaces the copy for the code the parent... (1 Reply)
Discussion started by: xyyz
1 Replies
3. Shell Programming and Scripting
Hello.
I have a global function name func1() that I am sourcing in from script A. I call the function from script B. Is there a way to find out which script called func1() dynamically so that the func1() can report it in the event there are errors?
Thanks (2 Replies)
Discussion started by: yoi2hot4ya
2 Replies
4. Programming
Hello,
How many child processes are actually created when running this code ?
#include <signal.h>
#include <stdio.h>
int main () {
int i ;
setpgrp () ;
for (i = 0; i < 10; i++) {
if (fork () == 0) {
if ( i & 1 ) setpgrp () ;
printf ("Child id: %2d, group: %2d\n", getpid(),... (0 Replies)
Discussion started by: green_dot
0 Replies
5. Shell Programming and Scripting
Hello,
How many child processes are actually created when running this code ?
#include <signal.h>
#include <stdio.h>
int main () {
int i ;
setpgrp () ;
for (i = 0; i < 10; i++) {
if (fork () == 0) {
if ( i & 1 ) setpgrp () ;
printf ("Child id: %2d, group: %2d\n",... (1 Reply)
Discussion started by: green_dot
1 Replies
6. UNIX for Advanced & Expert Users
Hi,
Is there a way I can kill all the child processes of a process, given its process id.
Many thanks in advance.
J. (1 Reply)
Discussion started by: superuser84
1 Replies
7. Programming
All,
Ok...so I know I *should* be able to control a process's stdin and stdout from the parent by creating pipes and then dup'ing them in the child. And, this works with all "normal" programs that I've tried. Unfortunately, I want to intercept the stdin/out of the scp application and it seems... (9 Replies)
Discussion started by: DreamWarrior
9 Replies
8. Windows & DOS: Issues & Discussions
I have a .NET application that remotely starts, stops, and gets status of Windows services and scheduled tasks. I would like to add the capability of starting, stopping, and getting status of remote AIX applications also. Based on some preliminary research, one option may be to use 3rd party .NET... (0 Replies)
Discussion started by: auser1
0 Replies
9. Shell Programming and Scripting
I am trying to implement the below using Ksh script on a Lx machine.
There is a file(input_file) with 100K records. For each of these records, certain script(process_rec) needs to be called with the record as input. Sequential processing is time-consuming and parallel processing would eat up... (2 Replies)
Discussion started by: APT_3009
2 Replies
10. Shell Programming and Scripting
is there a universal way of getting the children of a particular process? i'm looking for a solution that works across different OSes...linux, aix, sunos, hpux.
i did a search online and i kept finding answers that were specific to Linux..i.e. pstree.
i want to be able to specify a process... (2 Replies)
Discussion started by: SkySmart
2 Replies
fork(2) System Calls Manual fork(2)
Name
fork - create a new process
Syntax
#include <sys/types.h>
#include <unistd.h>
pid = fork()
pid_t pid;
Description
The system call causes creation of a new process. The new process (child process) is an exact copy of the calling process except for the
following:
o The child process has a unique process ID.
o The child process has a different parent process ID (that is, the process ID of the parent process).
o The child process has its own copy of the parent's descriptors. These descriptors reference the same underlying objects, so that, for
instance, file pointers in file objects are shared between the child and the parent, so that a on a descriptor in the child process
can affect a subsequent read or write by the parent. This descriptor copying is also used by the shell to establish standard input
and output for newly created processes as well as to set up pipes.
o The child processes resource utilizations are set to 0. For further information, see
Return Values
Upon successful completion, returns a value of 0 to the child process and returns the process ID of the child process to the parent
process. Otherwise, a value of -1 is returned to the parent process, no child process is created, and the global variable errno is set to
indicate the error.
Diagnostics
The system call fails and no child process are created under the following conditions:
[EAGAIN] The system-imposed limit {PROC_MAX} on the total number of processes under execution would be exceeded.
[EAGAIN] The system-imposed limit {CHILD_MAX} on the total number of processes under execution by a single user would be exceeded.
[ENOMEM] There is insufficient swap space for the new process.
See Also
execve(2), wait(2)
fork(2)