Sponsored Content
Top Forums Shell Programming and Scripting Troubles with pipes, fork, and dup2 Post 302873041 by dano88 on Monday 11th of November 2013 04:04:38 AM
Old 11-11-2013
Firstly, thank you for your answer. But I have one question: what would you do to automate it?
 

10 More Discussions You Might Find Interesting

1. Filesystems, Disks and Memory

PIPEs and Named PIPEs (FIFO) Buffer size

Hello! How I can increase or decrease predefined pipe buffer size? System FreeBSD 4.9 and RedHat Linux 9.0 Thanks! (1 Reply)
Discussion started by: Jus
1 Replies

2. UNIX for Advanced & Expert Users

Interprocess communication using pipes and fork

I'm very worried. I have an assignment that is due in 3 weeks, and also tute exercises which I can't seem to understand and work out. Okay, the question: The parent process will convert the command arguments into integer values using atoi() and store them into an integer array which you will... (2 Replies)
Discussion started by: scmay
2 Replies

3. Programming

Understanding the purpose of dup/dup2

I'm having difficulty understanding the purposes of using dup/dup2 when involving forks. for example, if we call fork() once, that is, we are creating a child process. In what cases would we need to use dup or dup2 to duplicate the file descriptors for standard output and standard error? What... (1 Reply)
Discussion started by: Yifan_Guo
1 Replies

4. Programming

a issue with dup2

Hi, i have in one program such a pice of code ................ static int old_stderr_handle = -1; static int old_stdout_handle = -1; log_handle = open(log_file_name,O_CREAT|O_RDWR,932); old_stderr_handle = dup(STDERR_FILENO); if (dup2(log_handle,STDERR_FILENO) < 0) { //... (1 Reply)
Discussion started by: vovan
1 Replies

5. UNIX for Advanced & Expert Users

dup2 filedescriptor redirecting output

int redirect() { int fd,rc; fd = open("sample.DAT",O_CREAT | O_RDWR , 00777 ); rc = dup2(fd , 1 ) ; close (fd ); return 0; } I used the above to redirect all the cout statements to sample.DAT. process is redirecting the output and I had two questions 1. All stdout/cout statements... (2 Replies)
Discussion started by: satish@123
2 Replies

6. Programming

Implementation of dup2

Hi all,I'm reading <Advanced programming in the UNIX environment>,that book asked the reader to implement a function which has same functions with dup2 without calling fcntl.Could anyone give me a tip?Any help will be appreciated.:) (8 Replies)
Discussion started by: homeboy
8 Replies

7. Programming

C++ socket, fork & pipes

Hello, I'm stuck and this is a matter which I need to resolve quite fast (but I couldn't post in the "Emergency" section); the problem is this : I have created a chat program in which the client sends the sentence to the server and then the server should send it to all the clients connected,... (2 Replies)
Discussion started by: timmyyyyy
2 Replies

8. Programming

C, unix, pipes, fork, recursion

Hi, I will try to keep my post as compressed as my title was. I am writing on pseudo code on a recursive function that I want to read from the one-above function-run and then give the result to the function-run down below until a stop is triggered. Example: $ ls -la | grep x | sort In my... (2 Replies)
Discussion started by: tarasque
2 Replies

9. UNIX for Advanced & Expert Users

Dup2 - for file descriptor opened by a different process

is it possible to duplicate file descriptors(opened by a different process) with the help of dup or dup2. the two process do not share parent child relationship as well. (2 Replies)
Discussion started by: replytoshishir
2 Replies

10. Programming

C++ stuck with dup2 and pipe

What this code should do is: there are parent.cpp and child.cpp. Parent will send whatever is in the buffer to child and child will send back whatever received to parent. I do not know what I am doing wrong. I am confused what is missing in the parent and what else I should include into the child.... (1 Reply)
Discussion started by: ramono
1 Replies
FORK(2) 							System Calls Manual							   FORK(2)

NAME
fork - spawn new process SYNOPSIS
fork( ) DESCRIPTION
Fork is the only way new processes are created. The new process's core image is a copy of that of the caller of fork. The only distinc- tion is the fact that the value returned in the old (parent) process contains the process ID of the new (child) process, while the value returned in the child is 0. Process ID's range from 1 to 30,000. This process ID is used by wait(2). Files open before the fork are shared, and have a common read-write pointer. In particular, this is the way that standard input and output files are passed and also how pipes are set up. SEE ALSO
wait(2), exec(2) DIAGNOSTICS
Returns -1 and fails to create a process if: there is inadequate swap space, the user is not super-user and has too many processes, or the system's process table is full. Only the super-user can take the last process-table slot. ASSEMBLER
(fork = 2.) sys fork (new process return) (old process return, new process ID in r0) The return locations in the old and new process differ by one word. The C-bit is set in the old process if a new process could not be cre- ated. FORK(2)
All times are GMT -4. The time now is 02:11 AM.
Unix & Linux Forums Content Copyright 1993-2022. All Rights Reserved.
Privacy Policy