Solved

Urgent! C Signal handling(UNIX)

Posted on 1998-04-19
7
291 Views
Last Modified: 2010-11-22
I am writing a C shell, and I want to launch a background
proc. How do I know when its terminateed?
And in general suppose I want to catch a signal. is there any way to do smth like that:

        IF (SOME SIGNAL)
           DO SMTH  
Thank you
0
Comment
Question by:danil082697
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
7 Comments
 
LVL 7

Expert Comment

by:busuka
ID: 1249840
I believe that signal( ) function is what you need.
 signal(2)

 NAME
      signal - specify what to do upon receipt of a signal

 SYNOPSIS
      #include <signal.h>

      void (*signal(int sig, void (*action)(int)))(int);

 DESCRIPTION
      signal() allows the calling process to choose one of three ways to
      handle the receipt of a specific signal.  sig specifies the signal and
      action specifies the choice.

I can put more if this is what you need.
0
 

Expert Comment

by:bing031398
ID: 1249841
The kernel will give you a SIGCLD or SIGCHLD when the shell's child teminates. Busuka is right. You can catch the signal using the signal function.
  Pass SIGCLD or SIGCHLD as the first parameter then pass the function to handle on the next parameter.
  Happy programming.
0
 
LVL 1

Author Comment

by:danil082697
ID: 1249842
well, suppose i need update several data structures, upon receiving a signal. But in signal(); i can only get an integer, then how do i get to the rest  of my structures.
0
Independent Software Vendors: We Want Your Opinion

We value your feedback.

Take our survey and automatically be enter to win anyone of the following:
Yeti Cooler, Amazon eGift Card, and Movie eGift Card!

 

Expert Comment

by:smithc
ID: 1249843
sounds like you need to set up some shared memory,,,,,
0
 

Accepted Solution

by:
bing031398 earned 200 total points
ID: 1249844
You have a lot of options:
  1. Make the structures global so the signal handler can change it.
  2. You can 'longjump' to a previously set location and set the data structures there.
  3. You can call an external function to do the update.
0
 
LVL 7

Expert Comment

by:busuka
ID: 1249845
danil, why you rejected my answer ? It was correct answer, but you
not wanted to hear explanations how to accomplish your task.
0
 

Expert Comment

by:upendra_swami
ID: 34194033
in my understanding, busuka is correct.
0

Featured Post

Independent Software Vendors: We Want Your Opinion

We value your feedback.

Take our survey and automatically be enter to win anyone of the following:
Yeti Cooler, Amazon eGift Card, and Movie eGift Card!

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

This tutorial is posted by Aaron Wojnowski, administrator at SDKExpert.net.  To view more iPhone tutorials, visit www.sdkexpert.net. This is a very simple tutorial on finding the user's current location easily. In this tutorial, you will learn ho…
Summary: This tutorial covers some basics of pointer, pointer arithmetic and function pointer. What is a pointer: A pointer is a variable which holds an address. This address might be address of another variable/address of devices/address of fu…
The goal of this video is to provide viewers with basic examples to understand and use structures in the C programming language.
Video by: Grant
The goal of this video is to provide viewers with basic examples to understand and use while-loops in the C programming language.

717 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question