Someone

#include <stdio.h>    #include <stdlib.h>    #include <errno.h>    #include <sys/types.h>    #include <sys/ipc.h>    #include <sys/sem.h>    int main(void)    {        key_t key1;        int semid1;static struct sembuf Decr = {0,-1,SEM_UNDO};static struct sembuf Incr = {0,1,SEM_UNDO};	key1 = ftok("reader.c", 'X');	semid1= semget(key1,2,IPC_CREAT | 0600);	semctl(semid1,0,SETVAL,1);	semctl(semid1,1,SETVAL,1);int i;for(i = 0; i<5; i++){semctl(semid1,0,SETVAL,0);semop(semid1,&Decr,1);printf("read\n");sleep(2);printf("done\n");semctl(semid1,0,SETVAL,1);semop(semid1,&Incr,1);sleep(4);}        return 0;    }