#include<errno.h>
#include<iostream>
#include<string>
#include<sys/types.h>
#include<sys/ipc.h>
#include<unistd.h>
#include<fcntl.h>
#include<semaphore.h>

using namespace std;

int main( int argc, char** argv ) {


  sem_t* mysem;
  int oflag = O_CREAT;
  mode_t mode = 0644;
  const char semname[] = "/mysem";
  unsigned value = 1;
  int sts;

  mysem = sem_open(semname,oflag,mode,value);

  char c = cin.get();

  char buf[1];

  cout << "Process 2 checking semaphore..." << endl;
  sem_wait( mysem );
  cout << "Process 2 in critical section" << endl;
  int fd = open( "file.txt", O_RDWR );
  read( fd, buf, 1 );
  cout << buf[0] << endl;
  sem_post( mysem);
  close( fd );
  cout << "The process unlocked the critical sectioin" << endl;
  cin.get();

  return 0;
}