/***
 *	Compile:  g++ -o copycpp -pthread exmutex.cpp  
 ***/
#include <cstdlib>
#include <fstream>
#include <iostream>
#include <pthread.h>
#define  MAX 5
#define	BLOCK 1024

#if defined(__cplusplus)
extern "C"
#endif

using namespace std;

void * read_file( void *);

/***       This is global ***/
pthread_mutex_t lock_it  = PTHREAD_MUTEX_INITIALIZER;

int main(int argc, char *argv[]) {
  int             i;
  int	  save_status = 0;
  pthread_t       thread_id[MAX];

  if ( argc < 2 || argc > MAX+1 ){           /* check arg list       */
    cout << "argc is " << argc << " MAX is " << MAX <<endl; 
    exit( 1 );
  }
  
  cout << "Copying the files named on the command line\n";

  for (i = 0; i < argc - 1; ++i) {              /* generate threads     */

    if( pthread_create(&thread_id[i], NULL, read_file, static_cast<void *> (argv[i + 1])) != 0) {
      cout << "pthread_create failure\n"; 
      exit( 2 );
    }
    cout << "Created thread " << i << endl;
  }

  void *result;  //Need a place to store return value from each thread
  for (i = 0; i < argc - 1; ++i){               /* wait for each thread */
    if ( pthread_join(thread_id[i], &result) > 0 ) {
      cout <<  "pthread_join failure\n"; 
      exit( 3 );
    }
    if (*(static_cast<int*>(result)) > save_status) {
      save_status = *(static_cast<int*>(result));
      cout << "Thread " << i << " returns " << *(static_cast<int*>(result)) << endl;
    }
    delete static_cast<int*>(result);  //Have to free memory allocated in the thread
  }

  pthread_mutex_destroy(&lock_it); //The mutex is no longer needed
  if (save_status == 0 )
    cout << "\nAll files copied\n";
  return (0);
}
/***
 *      Open and copy to stdout the contents of the file
 ***/
void  *read_file(void *filename) {
  char buffer[BLOCK];
  ifstream fd;
  int *pfid = new int; //This address will be returned, need it to be on the heap
  *pfid = 0;
  pthread_t	tid;

  tid = pthread_self(); //Which thread is it
  pthread_mutex_lock(&lock_it);	/* lock stdout */
  cout << "Entered the thread function, tid = " << static_cast<int>(tid) << endl;
  pthread_mutex_unlock(&lock_it);   /*unlock stdout */

//Open the file specified on the command line
  fd.open(static_cast<char *>(filename)); 
  if(!fd) {
//   File open failed
        *pfid = 1;
	pthread_exit(static_cast<void *>(pfid));
  }

  pthread_mutex_lock(&lock_it);	/* lock stdout */
  cout << "Thread " << static_cast<int>(tid) << " copying file " << static_cast<char *>(filename) << endl;
  pthread_mutex_unlock(&lock_it);   /*unlock stdout */

//The file will be copied in this loop
  pthread_mutex_lock(&lock_it);	/* lock stdout */
  while (fd.getline(buffer,BLOCK) > 0)
	cout << buffer << endl;
  pthread_mutex_unlock(&lock_it);   /*unlock stdout */

  fd.close(); //The file is no longer needed
//*pffid should still be 0
  pthread_exit(static_cast<void *>(pfid)); //Returned success
}