hi experts(novice people can stay away as it is no child's game),
i am developing a script which works like recycle bin of windows.
the problem i am facing is that when ever i am trying to delete a file which is situated in parent directory or parent's parent directory i am unable to... (1 Reply)
Hi, as I understand fork(), it makes a copy of the parent which becomes a child. But is there anyway to make three children for that one parent. So in other words, if I look up the getppid() of the children, I want them to have the same value??
Thanks in advance to any help! (1 Reply)
I want take a flash backup by flar command for specific files like:
/ , /boot, /tmp
I am trying this command but its not working
# flar -n archive1 -f /,/boot,/tmp -F -c /home/arc1.flar
Please can any body help me __.____._ (2 Replies)
Hello friends,
I have compiled the kernel .
But now i am facing the problem as to how we can create the initrd.img for the specific kernel.
I was compiling the 2.6.29 kernel.
to create initrd.img for 2.6.29
what i did is :
cd /boot
mkinitramfs-kpkg -o initrd.img-2.6.29 2.6.29... (2 Replies)
Hi Everyone,
Please refer to attached test.zip.
Open a.htm, tested under IE, Safari, Firefox no problem, but ONLY google chrome fail, seems cannot use call parent javascript function under the child iframe.
Please advice.
Thanks (1 Reply)
Write a program using select, which will create some number of child processes that continuously send text messages to the parent process using pipes. Each child has its own pipe that it uses to communicate with the parent. The parent uses select () to decide what pipes should be processed to... (1 Reply)
The task I have to do is something along the lines "I receive some input and based on the first character I send it through pipe to one of the children to print".
The scheme it is based on is 1->2; 1->3; 1->4; 2 will print all the input that starts with a letter, 3 will print all the input that... (2 Replies)
Discussion started by: Ildiko
2 Replies
LEARN ABOUT PLAN9
rendezvous
RENDEZVOUS(2) System Calls Manual RENDEZVOUS(2)NAME
rendezvous - user level process synchronization
SYNOPSIS
#include <u.h>
#include <libc.h>
ulong rendezvous(ulong tag, ulong value)
DESCRIPTION
The rendezvous system call allows two processes to synchronize and exchange a value. In conjunction with the shared memory system calls
(see segattach(2) and fork(2)), it enables parallel programs to control their scheduling.
Two processes wishing to synchronize call rendezvous with a common tag, typically an address in memory they share. One process will arrive
at the rendezvous first; it suspends execution until a second arrives. When a second process meets the rendezvous the value arguments are
exchanged between the processes and returned as the result of the respective rendezvous system calls. Both processes are awakened when the
rendezvous succeeds.
The tag space is common to processes in the same file name space, so rendezvous only works between processes in the same file name space.
If a rendezvous is interrupted the return value is ~0, so that value should not be used in normal communication.
SOURCE
/sys/src/libc/9syscall
SEE ALSO segattach(2), fork(2)DIAGNOSTICS
Sets errstr.
BUGS
The correlation of rendezvous tags and file name space is a historical accident. If two unrelated processes happen to be in the same name
space and do a rendezvous, trouble will result. The solution is to call rfork(RFNAMEG) (see fork(2)) in programs that use rendezvous
unless they need to share the name space with their parent. This is especially important in Alef programs.
RENDEZVOUS(2)