求救！！！子进程和父进程要交互的访问一个变量，怎么实现。

#include <stdio.h>;
#include <stdlib.h>;
#include <unistd.h>;
#include<sys/types.h>;
#include<sys/time.h>;
#include<signal.h>;
#include<fcntl.h>;

#define THINKER_NUM 5

#define LEFT 0
#define RIGHT 1

#define USING 1
#define NO_USE 0

#define OTHER_STATUS 0
#define THINKING_STATUS 1
#define HUNGRY_STATUS 2
#define EATING_STATUS 3

typedef struct think {
                  int u_id;
                  int u_status;
                  }Thinker;

void initial(Thinker thinkers[THINKER_NUM],int chop_status[THINKER_NUM])
{
int i;
for(i=0;i<THINKER_NUM;i++)
{
  thinkers.u_id=i;
  thinkers.u_status=THINKING_STATUS;
  chop_status=NO_USE;
}
}

void read_share(Thinker thinkers[THINKER_NUM],int chop_status[THINKER_NUM])
{
  int fd;
  int n;
  while (open("share.lock",O_RDONLY)!=-1);
  link("share.dat","share.lock";
  while((fd=open("share.dat",O_RDONLY))<=0)
  {
perror("file open error in read_share \n";
sleep(1);
  }
  n=sizeof(thinkers);
  if(read(fd,thinkers,n)<0)
perror("file read error in read_share thinkers\n";
  n=sizeof(chop_status);
  if(read(fd,chop_status,n)<0)
perror("file read error in read_share chop_static\n";
  close(fd);
  unlink("share.lock";
}

void write_share(Thinker thinkers[THINKER_NUM],int chop_status[THINKER_NUM])
{
  int fd;
  int n;
  while (open("share.lock",O_WRONLY)!=-1) ;
  link("share.dat","share.lock";
  while((fd=open("share.dat",O_WRONLY|O_TRUNC))<=0)
  {
perror("file open error in write_share\n";
sleep(1);
  }
  n=sizeof(thinkers);
  if(write(fd,thinkers,n)<n)
perror("file write error in write_share thinkers\n";
  n=sizeof(chop_status);
  if(write(fd,chop_status,n)<n)
perror("file write error in write_share chop_static\n";
  close(fd);
  unlink("share.lock";
}

void drop(int u,int first)
{
  void try(int );
  Thinker thinkers[THINKER_NUM];
  int chop_status[THINKER_NUM];
  read_share(thinkers,chop_status);
  if(first==RIGHT)
chop_status[(u+1)%THINKER_NUM]==NO_USE;
  else
chop_status[u%THINKER_NUM]==NO_USE;
  write_share(thinkers,chop_status);
  printf("now drop :%d:\n",u);
  sleep(3);
/*  try(u); */
  exit(0);
}
void reset_left(int u)
{
  void try(int );
  Thinker thinkers[THINKER_NUM];
  int chop_status[THINKER_NUM];
  printf("now in rest_left : %d :\n",u);
  read_share(thinkers,chop_status);
  chop_status[u%THINKER_NUM]==NO_USE;
  thinkers.u_status=THINKING_STATUS;
  write_share(thinkers,chop_status);
  printf("is thinking :%d:\n",u);
  sleep(5+rand()%5); /*thinking */
/* try(u);  */
  exit(0);

}



void reset_right(int u)
{
  void reset_left(int );
  Thinker thinkers[THINKER_NUM];
  int chop_status[THINKER_NUM];
  read_share(thinkers,chop_status);
  printf("now reset right : %d :\n",u);
  chop_status[(u+1)%THINKER_NUM]==NO_USE;
  write_share(thinkers,chop_status);
  sleep(1);
  reset_left(u);
}

void second(int u,int first)
{
  void drop(int, int );
  void reset_right(int );
  Thinker thinkers[THINKER_NUM];
  int chop_status[THINKER_NUM];
  printf("now in second :%d:\n",u);
  read_share(thinkers,chop_status);
  if(first==RIGHT)
  {
if(chop_status[u%THINKER_NUM]==NO_USE)
{
   chop_status[u%THINKER_NUM]=USING;
   thinkers.u_status=EATING_STATUS;
   write_share(thinkers,chop_status);
   printf(":now process : %d: is eating\n",u);
   sleep(5); /*the eating time as to crit */
   thinkers.u_status=OTHER_STATUS;
   write_share(thinkers,chop_status);
   reset_right(u);
}
else if(chop_status[u%THINKER_NUM]==USING)
   drop(u,first);
  }
  else
  {
if(chop_status[(u+1)%THINKER_NUM]==NO_USE)
{
   chop_status[(u+1)%THINKER_NUM]==USING;
   thinkers.u_status=EATING_STATUS;
   write_share(thinkers,chop_status);
   printf("now process : %d : is eating \n",u);
   sleep(5);
   thinkers.u_status=OTHER_STATUS;
   write_share(thinkers,chop_status);
   reset_right(u);
}
else if(chop_status[(u+1)%THINKER_NUM]==USING)
   drop(u,first);
  }
}

void wait(int u,int first)
{
  void second(int, int);
  Thinker thinkers[THINKER_NUM];
  int chop_status[THINKER_NUM];
  if(first==RIGHT)
printf("now in wait one :%d:  wait for right \n",u);
  else
printf("now in wait one :%d: wait for left \n",u);
  BEG:
  read_share(thinkers,chop_status);
  if(first==RIGHT)
  {
if(chop_status[(u+1)%THINKER_NUM]==NO_USE)
   {
   chop_status[(u+1)%THINKER_NUM]==USING;
   write_share(thinkers,chop_status);
   second(u,first);
   }
else if(chop_status[(u+1)%THINKER_NUM]==USING)
{
   printf("chop now busy wait pid %d:  chopstick %d\n",u,(u+1)%THINKER_NUM);
   sleep(1);
   goto BEG;
}
  }
  else
  {
if(chop_status[u%THINKER_NUM]==NO_USE)
   {
   chop_status[u%THINKER_NUM]==USING;
   write_share(thinkers,chop_status);
   second(u,first);
   }
else if(chop_status[u%THINKER_NUM]==USING)
{
printf("chop now busy wait %d: chopstatic  %d\n",u,u%THINKER_NUM);
sleep(1);
goto BEG;
  }
}
}
void try(int u)
{
  void wait(int,int );
  Thinker thinkers[THINKER_NUM];
  int chop_status[THINKER_NUM];
  int first;
  read_share(thinkers,chop_status);
  thinkers.u_status=HUNGRY_STATUS;
  write_share(thinkers,chop_status);
  if(rand()%2==1)
first=RIGHT;
  else
first=LEFT;
  printf("now try porcess: %d : in the first is %d\n",u,first);
  wait(u,first);
}

void LehmannRabin(int u)
{
void try(int u);
Thinker thinkers[THINKER_NUM];
int chop_status[THINKER_NUM];
read_share(thinkers,chop_status);
printf("now lehmannrabin :%d:\n",u);
sleep(rand()%5);
thinkers.u_status=HUNGRY_STATUS;
write_share(thinkers,chop_status);
try(u);
}

int main(void)
{
  int i;
  pid_t pid;
  int fd;
  int n;
  Thinker thinkers[THINKER_NUM];
  int chop_status[THINKER_NUM];
  initial(thinkers,chop_status);
  if((fd=open("share.dat",O_CREAT|O_TRUNC|O_WRONLY,0777))==0)
  {
perror("file open error in main\n");
exit(0);
  }

  n=sizeof(thinkers);
  if(write(fd,thinkers,n)<n)
perror("write fifo error in main\n");

  n=sizeof(chop_status);
  if(write(fd,chop_status,n)<n)
perror("write fifo error in main\n");
  close(fd);
  for(i=0;i<THINKER_NUM;i++)
  {
pid=fork();
if(pid==0)
{
   srand((unsigned int)time(NULL));
   LehmannRabin(i);
}
else if(pid>;0)
{
   sleep(1);
   continue;
}
else
   perror("fork error\n");
  }
exit(0);
}



请各位指点

运行一段时间后 share.dat的数据就没有了
不知道怎么回事