求解答啊！！！
#include <stdio.h>
#include <errno.h>
#include <fcntl.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/ipc.h>
#include <sys/shm.h>
#include <string.h>
#include <stdlib.h>
#define NAME "/tmp/lhb/myshm"
                                                                                
int main(int argc,char *argv[])
                                                                                
{
  int shmid;
  key_t key;
  char *w_addr;
                                                                                
  key = ftok(NAME,'a');
  if(key == -1)
  {
   printf("key erro\n");
  }
   printf("key = %d\n",key);
                                                                                
  if(argc != 2)
  {
    printf("argv erro\n");
  }
  shmid = shmget(key,1024,O_RDWR);
  printf("shmid = %d\n",shmid);
  if(shmid == -1)
  {
    printf("shmget erro\n");
    exit(-1);
  }
                                                                                
  w_addr = shmat(shmid,0,0);
  memset(w_addr,0,sizeof(w_addr));
  write(w_addr,argv[1],1024);
  exit(0);
                       &