I am trying my hand in networking programming in C, and got stuck in piping.
I was following some tutorial and did the forking like :
I want to have:
The client forks off a child. After the child is forked off, the parent process enters a second loop in which it continually reads and prints out status messages received from the child via a half-duplex pipe.
How to do the thing in bold?
Apologies , if it is a lame question..but how do we do that or some reference of the same would help me..
Dear All,
Would you tell me how I can passing a message along pipes?
I have built a token ring connected with pipes, but I don't know how to pass the message along it through the command line...
Thx.
Yours,
i- (1 Reply)
:(
Since I'm fairly new to the scene and don't have much experience in shell programming, I decided to check out the net for a useful script or two.
What I'm looking for is a script that would let me enter a PID and then show the process tree associated with it.
So it would display the (grand-)... (2 Replies)
Hi all,
I'm trying to write a program that has some data it wants to send through a filter program(in this case tr), and then recieve the output from that filter program. The way I'm trying to do it is by setting up two pipes between the programs and piping the data in through one pipe and back... (2 Replies)
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)
Hi
I have written a script using ftp to get files from one server and copy them to 2 dirrerent servers. I wish to call this script from a parent script that will check the number of files copied and run a check sum for each file. As the filenames for the files in the get portion of the script... (3 Replies)
Hi guys, I'm having some problem here, I'm studying pipes, and i want to create a shell in C and at this point a don't want to use semaphores, instead I want to use tricks. Straight to the doubt: I've a parent and a child process, and both of them has some code to execute, and the child process... (5 Replies)
1. The problem statement, all variables and given/known data:
I need to make an program that in a loop creates one parent and five children with fork(). The problem i'm trying to solve is how to delete the parent and child of the childīs process.
2. Relevant commands, code, scripts,... (0 Replies)
Hi everyone
i am very new to linux , working on bash shell.
I am trying to solve the given problem
1. Create a process and then create children using fork
2. Check the Status of the application for successful running.
3. Kill all the process(threads) except parent and first child... (2 Replies)
I have a simple client/server program I am using for learning purposes.
I have it setup so that after server is setup and listening it than goes into a loop where it accepts incoming client connections. After each connection, the client socket is than passed to a thread routine where it can be... (3 Replies)
Hi Forum.
I have this challenging issue that I'm hoping someone can help me.
I have a file that contains 3 different types of segments (AM00, AM01, AM32) in a hierarchy structure and I want to be able to pass the column key from the parent record to the children records.
AM00 - parent key:... (13 Replies)
Discussion started by: pchang
13 Replies
LEARN ABOUT MINIX
fork
FORK(2) System Calls Manual FORK(2)NAME
fork - create a new process
SYNOPSIS
#include <sys/types.h>
#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 except for the following:
The child process has a unique process ID.
The child process has a different parent process ID (i.e., the process ID of the parent process).
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 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.
The child starts with no pending signals and an inactive alarm timer.
RETURN VALUE
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 one or more of the following are true:
[EAGAIN] The system-imposed limit on the total number of processes under execution would be exceeded. This limit is configuration-
dependent. (The kernel variable NR_PROCS in <minix/config.h> (Minix), or <minix/const.h> (Minix-vmd).)
[ENOMEM] There is insufficient (virtual) memory for the new process.
SEE ALSO execve(2), wait(2).
3rd Berkeley Distribution May 22, 1986 FORK(2)