Login or Register to Ask a Question and Join Our Community

Sponsored Content
Full Discussion: fork() and the program is hanging...
Top Forums Programming fork() and the program is hanging... Post 302343634 by lipun4u on Thursday 13th of August 2009 06:16:59 AM
Old 08-13-2009
fork() and the program is hanging...
Consider the following code..
Code:
#include <unistd.h>
#include <sys/types.h>
#include <errno.h>
#include <stdio.h>
#include <sys/wait.h>
#include <stdlib.h>

int main()
{
    pid_t childpid;
    int retval;
    int status;

    childpid = fork();
    if(childpid >= 0)
    {
        if(childpid == 0)
        {
            printf("CHILD : I am the child process\n");
            printf("CHILD : Here's my PID : %d\n", getpid());
            printf("CHILD : My parent's PID is : %d\n", getppid());
            printf("CHILD : The value of my copy of childpid is : %d\n", childpid);
            printf("CHILD : Sleeping for 1 second...\n");
            sleep(1);
            printf("CHILD : Enter an exit value (0 to 255) : ");
            scanf("%d\n", &retval);
            printf("CHILD : Goodbye\n");
            exit(retval);
        }
        else
        {
            printf("PARENT : I am the parent process\n");
            printf("PARENT : Here's my PID : %d\n", getpid());
            printf("PARENT : The value of my copy of childpid is : %d\n", childpid);
            printf("PARENT : I will now wait for my child to exit\n");
            wait(&status);
            printf("PARENT : Child's exit code is : %d", WEXITSTATUS(status));
            printf("PARENT : Goodbye\n");
            exit(0);
        }
    }
    else
    {
        perror("fork error");
        exit(0);
    }
}

Why the program hangs after the scanf statement ???
 

10 More Discussions You Might Find Interesting

1. UNIX for Dummies Questions & Answers

how to tell if process is hanging

On Solaris 8.. 28166 user 3693M 2736M sleep 5 0 0:05.38 0.0% PROCESS/4 How can I tell if this process is doing anything or just hanging? (2 Replies)
Discussion started by: dangral
2 Replies

2. AIX

multi threaded program is hanging

I have a Multithreaded program which is hanging on AIX. OS Version: AIX 5.2 and thread library version : 5.2.0.75 We Initiate the process with 50 threads..when we are disconnecting from the process it hangs.There is lots of other stuff involved here.I am just sending the piece of the problem with... (0 Replies)
Discussion started by: hikrishn
0 Replies

3. Solaris

hanging sockets!??!

hi all, i had a program which created a socket on port 7113, but for some reason the program was hunbg and I had to Ctrl+c it. I ran the program for a couple of times and now when I do a netstat -a I see that these sockets are lingering and that might be the reason why my program is not... (1 Reply)
Discussion started by: Naanu
1 Replies

4. Programming

C++ How to use pipe() & fork() with stdin and stdout to another program

Hi, Program A: uses pipe() I am able to read the stdout of PROGAM B (stdout got through system() command) into PROGRAM A using: * child -> dup2(fd, STDOUT_FILENO); -> execl("/path/PROGRAM B", "PROGRAM B", NULL); * parent -> char line; -> read(fd, line, 100); Question:... (2 Replies)
Discussion started by: vvaidyan
2 Replies

5. Programming

Change Pseudo Code to C Program (print and fork)

I am very new at programming and this is probably an easy question, but I am desperate. I need to change this low level code into a C program that I can run so I can print out every "A" that appears with the fork() command. You help is greatly appreciated. PRINT A p=fork() if( p == 0) {... (0 Replies)
Discussion started by: tpommm
0 Replies

6. Shell Programming and Scripting

Run shell script from C program by calling fork and execl

I need to write a c program that uses the fork and excel system calls to run the shell script mode invoked like this: "./mode 644 ls -l" (that is the argumetns will always be 644 ls -l) here's the mode script: #!/bin/sh octal="$1" shift find . -maxdepth 1 -perm $octal -exec $@ {} \; ... (3 Replies)
Discussion started by: computethis
3 Replies

7. Programming

How forbid use fork() in exec() program.

Hello World! I am writing code in C++ which have to launch another application X using exec(). I would like to set some limits on it using setrlimit etc... My problem is that i don't know how to forbid using fork() and strlimit by application X. How can i do it? (3 Replies)
Discussion started by: kzi
3 Replies

8. Shell Programming and Scripting

sed hanging

/bin/sed -n '$q;5633653,0 p' lfile lfile is a log file that is being updated several times a second. so, the command above figures out the line number it wants in the lfile and then proceeds to output all lines from that line number to the end of the file. the problem is, the end of the... (2 Replies)
Discussion started by: SkySmart
2 Replies

9. UNIX for Dummies Questions & Answers

netstat -a is hanging??

Hi, I am on Solaris 10 server. I wanted to see a port is ESTABLISHED or in the LISTEN mode. But when I do netstat -a |grep 22205, it's hanging. I have waited over two minutes. Is it possible, something else is wrong on the server? I don't see anything on /var/adm/messages file. ... (3 Replies)
Discussion started by: samnyc
3 Replies

10. Shell Programming and Scripting

Sftp hanging

Hi All, I am transfering a file through sftp. But the script is hanging at exit occasionally. I am suspecting that sftp is hanging due to buffer size issue. If that is the case can any body suggest a solution. Please find the code. echo "cd /${CUST_ID}/inbound/${SAFET_ID}" >... (0 Replies)
Discussion started by: Girish19
0 Replies

LEARN ABOUT DEBIAN

paps

PAPS(1) 						      General Commands Manual							   PAPS(1)

NAME

       paps - UTF-8 to PostScript converter using Pango

SYNOPSIS

       paps [options] files...

DESCRIPTION

       paps reads a UTF-8 encoded file and generates a PostScript language rendering of the file. The rendering is done by creating outline curves
       through the pango ft2 backend.

OPTIONS

       These programs follow the usual GNU command line syntax, with long options starting with  two  dashes  (`-').   A  summary  of  options	is
       included below.

       --landscape
	      Landscape output. Default is portrait.

       --columns=cl
	      Number of columns output. Default is 1.
	      Please notice this option isn't related to the terminal length as in a "80 culums terminal".

       --font=desc
	      Set the font description. Default is Monospace 12.

       --rtl  Do right to left (RTL) layout.

       --paper ps
	      Choose paper size. Known paper sizes are legal, letter and A4. Default is A4.

       Postscript points
	      Each postscript point equals to 1/72 of an inch. 36 points are 1/2 of an inch.

       --bottom-margin=bm
	      Set bottom margin. Default is 36 postscript points.

       --top-margin=tm
	      Set top margin. Default is 36 postscript points.

       --left-margin=lm
	      Set left margin. Default is 36 postscript points.

       --right-margin=rm
	      Set right margin. Default is 36 postscript points.

       --gutter-width=gw
	      Set gutter width. Default is 40 postscript points.

       --help Show summary of options.

       --header
	      Draw page header for each page.

       --markup
	      Interpret the text as pango markup.

       --lpi  Set the lines per inch. This determines the line spacing.

       --cpi  Set the characters per inch. This is an alternative method of specifying the font size.

       --stretch-chars
	      Indicates  that  characters  should be stretched in the y-direction to fill up their vertical space. This is similar to the texttops
	      behaviour.

AUTHOR

       paps was written by Dov Grobgeld <dov.grobgeld@gmail.com>.

       This manual page was written by Lior Kaplan <kaplan@debian.org>, for the Debian project (but may be used by others).

								  April  17, 2006							   PAPS(1)
All times are GMT -4. The time now is 01:10 AM.
Unix & Linux Forums Content Copyright 1993-2022. All Rights Reserved.
Privacy Policy