#include <sys/types.h>
#include <sys/stat.h>
#include <sys/file.h>
#include <unistd.h>
#include <stdio.h>
#include <fcntl.h>

void main()
{
 int fd;
 struct flock *lck; 

 printf("opening\n",fd); 
// fd=open("/tmp/watchme/locked",O_RDWR|O_CREAT,00666);
 fd=open("/tmp/watchme/locked",O_RDWR|O_CREAT,00666);

// printf(fd,"DEPP....\n"); 
 lck=malloc(sizeof(flock));
 lck->l_type=F_WRLCK;
 printf("fd=%d\n",fd);
 fcntl(fd,F_SETLK,lck);
 sleep(3600);
 lck->l_type=F_UNLCK;
 fcntl(fd,F_SETLK,lck);
 close(fd);
}