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7.6

How can I access an array in a parent process from a child process? (fork)

Asked by shadow_shooter in C Programming Language, Linux Programming, Linux Networking

Tags: C, Linux, Fedora, Ubuntu, Programming, Child, Parent

Hello,

I created two arrays in a parent process. What I want to do is accessing this array from a child process. I know I can do this by using a shared memory but I don't want to use it. Is there a way to overcome this problem?

If I make sure parent process doesn't end before child processes complete, is it sufficient to use the array that the parent process created? As far as I experienced, it is not. I still see garbage values in both arr1 and arr2.

Can anyone please help me? 
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#include <stdio.h>
#include "functions.h"
 
int main()
{
	int pid1, pid2;
	int arr1[248], arr2[248], grid[496] i, j;
	FILE *fp;
	fp = fopen("unsorted.txt", "r"); 
	if(fp == NULL)
	{
		printf("An error has occured during reading the file. Check if the file name or path is correct.\n");
 
	}
 
	pid1=fork();
	if(pid1==0)
	{
		pid2=fork();
		
		if(pid2==0)
		{
			//SECOND CHILD               
			heapSort(arr1, 248);  //PROBLEM IS HERE: arr1 is not filled though it was, by Parent process.
			printArray(arr1,248);
		}
		else
		{
			//FIRST CHILD
			wait(&pid2);
			heapsort(arr2,248);
			printArray(arr2,248);
		}
	}
	else
	{		
		while(fscanf(fp, "%d", &grid[count]) != EOF) 
		{
			count++;
		}
		for(i=0; i<248; i++)
		{
			arr1[i]=grid[i];
		}
 
		i=0;
		for(j=248; j<496; j++)
		{
			arr2[i]=grid[j];
			i++;
		}
		wait(&pid1);
		fclose(fp);
	}
}
[+][-]03/21/09 08:48 AM, ID: 23947738Expert Comment

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[+][-]03/21/09 11:16 AM, ID: 23948217Expert Comment

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[+][-]03/21/09 11:26 AM, ID: 23948262Accepted Solution

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About this solution

Zones: C Programming Language, Linux Programming, Linux Networking
Tags: C, Linux, Fedora, Ubuntu, Programming, Child, Parent
Sign Up Now!
Solution Provided By: Kdo
Participating Experts: 1
Solution Grade: B
 
 
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