Prgm 3

#include<stdio.h>
#include<string.h>
#include<fcntl.h>
#include<unistd.h>

int main(int argc,char* argv[])                                    //Terminal 1
{
   int fd;
   struct flock lock;
   printf("Opening file %s",argv[1]);
   fd=open(argv[1],0,RDONLY);
   printf("Locking files= %s",argv[1]);
   lock.l_type=F_RDLCK;
   lock.l_start=-99;
   lock.l_whence=SEEK_END;
   lock.l_len=100;
   fcntl(fd,F_SETLKW,&lock);
   printf("Unlocking the file= %s",lock.l_pid,argv[1]);
   printf("Press enter to unlock the file %s",argv[1]);
   getchar();
   printf("Unlocking the file %s",argv[1]);
   lock.l_type=F_UNLCK;
   fcntl(fd,F_SETLKW,&lock);
   printf("File %s is unlock",argv[1]);
   close(fd);
   return 0;
}


#include<stdio.h>
#include<string.h>
#include<fcntl.h>
#include<unistd.h>

int main(int argc,char* argv[])                                       //Terminal 2
{
   int fd,num;
   struct flock,lock;
   char buf[100];
   printf("Opening file %s",argv[1]);
   fd=open(argv[1],0,RDONLY);
   printf("Checking the current lock on files %s",argv[]);
   lock.l_type=F_WRLCK;
   lock.l_start=-99;
   lock.l_len=100;
   fcntl(fd,FGETLCK,&UNLCK);
   if(locl.l_type!=F_UNLCK)
     {
        printf("Process with id %d has %c lock on file %s",lock.l_pid(lock.l_type==F_WRLCK)"W":"R",argv[1]);
        return 0;
     }
     printf("Locking the file %s",argv[1]);
     lock.l_type=F_WRLCK;
     lock.l_start=-99;
     lock.l_whence=SEEK_END;
     lock.l_len=100;
     fcntl(fd,F_SETLK,&lock);
     printf("Process with id %d has locked the file in %s",lock.l_pid,argv[1]);
     printf("Reading the last 50 bytes from %s",argv[1]);
     lseek(fd,-50,SEEK_END);
     num=read(fd,buf,50);
     buf[num]='\0';
     printf("Last 50 bytes= %s,buf");
     printf("Press enter key to release");
     getchar();
     printf("Unlocking file= %s",argv);
     lock.l_type=F_UNLCK;
     fcntl(fd,F_SETLK,&lock);
     printf("%s file is unlock",argv[1]);
     close(fd);
     return 0;
}