passing 2D Array to recursion - c

Question

I am trying to make calculations with using fork in C.
I have a 2D array with members {1,2,3,4}, I have a function to get square for each member in the array. I will call this function with child processes.
For example for 3 child process output will be like this;
1.Child
1 4
9 16
----------
2.Child
1 16
81 256
----------
3.Child
1 256
6561 65536
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h>
int matrix[2][2] = {1, 2, 3 ,4 } ;
int main(){
forkFork(3);
}
void forkFork(int counter)
{
pid_t pid;
if(counter == 0)
{
exit(0);
}
if(counter > 0)
{
if ((pid = fork()) < 0)
{
perror("fork error :(");
}
else if (pid == 0)
{
matrixPower(matrix);
print(matrix);
}
else if(pid > 0)
{
forkFork(counter - 1);
}
}
}
void matrixPower(int m[2][2])
{
int i,j,k;
int result = 0;
for (i = 0; i < 2; i++)
{
for (j = 0; j < 2; j++)
{
result = matrix[i][j]*matrix[i][j];
m[i][j] = result;
result = 0;
}
}
}
void print(int a[2][2])
{
int row, col ;
for( row = 0; row < 2; row++ )
{
for( col = 0; col < 2 ; col++ )
{
printf("%d\t", a[row][col]);
}
puts("");
}
printf("-------------------------------\n");
}
I could not find a way to pass new array to recursion function...

Answer 1

The problem with your solution is that all forked processes are created by the main/parent process. Therefore, each forked process just inherits the address space of the parent whose matrix values are always {1, 2, 3, 4}. The solution is for each modifying process to create its child process. Thus a new child process inherits the modified matrix.
See my solution below for forkFork function which works as expected.
void forkFork(int counter)
{
pid_t pid;
if(counter == 0)
{
exit(0);
}
if(counter > 0)
{
if ((pid = fork()) < 0)
{
perror("fork error :(");
}
else if (pid == 0)
{
matrixPower(matrix);
print(matrix);
forkFork(counter - 1);
}
}
}