06-17-2002
Basically, you only have to fork() several childs whose "work" is to be blocked on accept().
As all childs are blocked there, when some connection arrives the kernel will awake one of the child processes, so it will go on after accept(), doing its "work".
Some operating systems dont allow blocking on accept(), so the childs are blocked in a file instead.( which, by the way, its more convenient.)
9 More Discussions You Might Find Interesting
1. Shell Programming and Scripting
i need the a c program that simulates the "ls" command:b: (5 Replies)
Discussion started by: madhu.it
5 Replies
2. Shell Programming and Scripting
Hi,
I am having an input file which contains a group of words,if one specific word comes which goes to next line.
example:
input file===>
shashi country= india comapny= none shashi shashi company= NONE shashi=my name
output===>
shashi country= india comapny= none
shashi
shashi... (6 Replies)
Discussion started by: hegdeshashi
6 Replies
3. Programming
Hi guys, I'm trying to write a little program that will fill up my harddrive and will log the process during this.
Now I've come up with this:
#include <stdio.h>
void main(void) {
char cmd1;
char cmd2;
int i=1;
sprintf(cmd2, "df -h");
while (i<=5)
{
system("dd... (3 Replies)
Discussion started by: Tiglet
3 Replies
4. UNIX for Dummies Questions & Answers
I have to
Write a program in C that recognizes the following commands and translates them into much simpler ones
Commands to recognize shorter command
list L
cd dir C - dir_length - dir
get file_name G - file_name_length - file_name
Long commands are read from the standard input and... (1 Reply)
Discussion started by: aintour
1 Replies
5. Homework & Coursework Questions
I have to
Write a program in C that recognizes the following commands and translates them into much simpler ones
Commands to recognize shorter command
list
L
cd dir
C - dir_length - dir
get file_name G - file_name_length - file_name
Long commands are read from the standard input... (1 Reply)
Discussion started by: aintour
1 Replies
6. Shell Programming and Scripting
Hello..
I want to take back up from server to local machine and i dont know how to do it using cron and sftp . I can do it by manually typing password in the terminal and taking the back up. How to create a 'backup.sh' file for doing all the back up process and shut down automatically after... (1 Reply)
Discussion started by: deepoos
1 Replies
7. Shell Programming and Scripting
I need help with the following.
1) Write a program in any language that takes a single integer array parameter and returns the decimal average of the input values.
2) Write a program, in any language, that prints the integers from 1 to 10, along with a cumulative sum of the integers printed... (1 Reply)
Discussion started by: sqa4life
1 Replies
8. Shell Programming and Scripting
Hi,
Here is my question:
I want a shell script which I name as 'del', and can be used as del(string).
when run del(string), it will delete several directories at different locations in my system,like:
rm -fr /lustre/fs/scratch/user/$string
rm -fr /home/user/$string
rm -fr... (4 Replies)
Discussion started by: 1988PF
4 Replies
9. UNIX for Dummies Questions & Answers
I am hoping someone can give me a good free web resource for writing code to compile a binary executable. I am getting fairly decent at writing shell script, are the .f files just shell scripts? Also, I don't know where to begin on the makefiles. The reason I am curious is because I have been... (6 Replies)
Discussion started by: butson
6 Replies
FORK(2) BSD System Calls Manual FORK(2)
NAME
fork -- create a new process
LIBRARY
Standard C Library (libc, -lc)
SYNOPSIS
#include <unistd.h>
pid_t
fork(void);
DESCRIPTION
fork() causes creation of a new process. The new process (child process) is an exact copy of the calling process (parent process) except for
the following:
o The child process has a unique process ID.
o The child process has a different parent process ID (i.e., 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 an lseek(2) on a descriptor in the
child process can affect a subsequent read(2) or write(2) 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 process' resource utilizations are set to 0; see setrlimit(2).
In general, the child process should call _exit(2) rather than exit(3). Otherwise, any stdio buffers that exist both in the parent and child
will be flushed twice. Similarly, _exit(2) should be used to prevent atexit(3) routines from being called twice (once in the parent and once
in the child).
In case of a threaded program, only the thread calling fork() is still running in the child processes.
Child processes of a threaded program have additional restrictions, a child must only call functions that are async-signal-safe. Very few
functions are asynchronously safe and applications should make sure they call exec(3) as soon as possible.
RETURN VALUES
Upon successful completion, fork() 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.
ERRORS
fork() will fail and no child process will be created if:
[EAGAIN] The system-imposed limit on the total number of processes under execution would be exceeded. This limit is configuration-depen-
dent.
[EAGAIN] The limit RLIMIT_NPROC on the total number of processes under execution by this user id would be exceeded.
[ENOMEM] There is insufficient swap space for the new process.
SEE ALSO
execve(2), setrlimit(2), vfork(2), wait(2), pthread_atfork(3)
STANDARDS
The fork() function conforms to ISO/IEC 9945-1:1990 (``POSIX.1'').
HISTORY
A fork() system call appeared in Version 6 AT&T UNIX.
BSD
June 10, 2004 BSD