mjhjmtu

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <time.h>
#include <string.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/wait.h>
#include <sys/ipc.h>
#include <sys/sem.h>
#include <sys/shm.h>
#include <sys/msg.h>
#include <sys/time.h>
#include <semaphore.h>
#include <fcntl.h>
#include <signal.h>
#include <stdbool.h>

#define TEST_ERROR if (errno) fprintf(stderr, 
 "%s:%d: PID=%5d: Error %d (%s)n", 
 __FILE__, 
 __LINE__, 
 getpid(), 
 errno, 
 strerror(errno));

struct individuals 
 pid_t writer;
;

struct shared_data 
 struct individuals vec[10]; 
;

int main()


 int shm_people_id;
 struct shared_data *people;

 shm_people_id = shmget(IPC_PRIVATE, sizeof(*people), 0600);
 TEST_ERROR;
 printf("My shm_people_id is %dn", shm_people_id);

 if((people = shmat(shm_people_id, NULL, 0)) == NULL) 
 printf("empty shmn");
 

 shmctl(shm_people_id, IPC_RMID, NULL); 

How can i check if a shared memory it's empty (by empty i mean without data putted in like in this code) after ataching to her?