shared memory problem

[c0d31]

im trying to get the following code to share a bit of memory btn a parent and child process.get input from parent execute in child , store result in shared memory then display in parent.
all im getting thus far is error 218. what m i missin !

#include <iostream>
#include <string>
#include <unistd.h>
#include <sys/wait.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/ipc.h>
#include <sys/shm.h>

#define MAX_SEQUENCE 10

typedef struct {
	long fib_sequence [MAX_SEQUENCE];
	int sequence_size;
} shared_data;

using namespace std;

long fib( unsigned long n )
{
	if( n <= 1 )
	{		
		return 1;
	}
	else 
	{
		return fib(n-1)+fib(n-2);
	}
}

void printFib( shared_data * me , unsigned long t )
{
		int ct = 0;
	
		me->fib_sequence[ct] = 0;
	
		for( unsigned long i = 0; i <= t ; i++ )
		{
		ct++;
		me->fib_sequence[ct] = fib( i );
		}

}

int main(int argc, char** argv)
{
	pid_t pID,wpi;
	int status,seg_id;
	shared_data * shared_mem;
	
	int vic = atol(argv[1]);
	
	if( (vic < 0) || (vic > MAX_SEQUENCE) )
	{
		cout<<"Number Error" <<endl;
		exit(1);
	}
	
	seg_id = shmget(IPC_PRIVATE,sizeof(shared_data), 0644 | IPC_CREAT );
	
	shared_mem = ( shared_data * ) shmat( seg_id , NULL , 0 );
	
	shared_mem->sequence_size = vic;
	
	pID = fork();

	if( pID == 0 )
	{
		printFib( shared_mem , vic);
	}
	else
	{
	  wpi = waitpid( pID,&status,WNOHANG);
	  
      if( !WIFEXITED(status) )
      {
         cerr << "waitpid() exited with an error: Status= " 
              << WEXITSTATUS(status) << endl;
      }
      else if( WIFSIGNALED(status) )
      {
         cerr << "waitpid() exited due to a signal: " 
              << WTERMSIG(status)    << endl;
      }
      else
      {
		  cout << shared_mem->fib_sequence <<endl;
		  shmdt(shared_mem);
		  shmctl(seg_id,IPC_RMID,NULL);
	  }		
	}
	
	return 0;
}

[c0d31]

stuck a wait(NULL) and it works . any ideas why the wait bit isnt processing ptherwise?