#include <iostream>
#include <cstdio>
#include <cstdlib>
using namespace std;
#include <pthread.h>
#include <unistd.h>

#define CHECK(x) \
	{ \
		int res = x; \
		if (res != 0) cerr << "PTHREAD ERROR: " << res << endl; \
	}
	
/** !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
 * mutex accessible by all threads
 */	
pthread_mutex_t mutex;

/**
 * data structure used to pass argument to thread
 * which contains the thread id
 */
typedef struct {
  int id;
  char msg[20];
} thread_data_t;
 
 
/**
 * thread to execute
 */
void *thread_code(void *argument) {

	// convert argument 
  	thread_data_t *data = (thread_data_t *) argument;

  	int n_repeat = 5;
  	while (n_repeat) {
  	
  		// critical section
  		// !!!!!!!!!! LOCK !!!!!!!!!!
  		CHECK( pthread_mutex_lock(&mutex) );
  		
  		cout << "thread(" << pthread_self() <<") ";
  		cout << ", id=" << data->id;
  		cout << ", msg=[" << data->msg << "]";
  		cout << ", repeat=" << n_repeat << endl;
  		
  		// !!!!!!!!!! UNLOCK !!!!!!!!!!
  		CHECK( pthread_mutex_unlock(&mutex) );
  		
  		--n_repeat;
  		sleep(1);
  	}
}

/** 
 * Main function
 */  
int main() {

	// array of threads
	pthread_t threads[10];
	// array of data for threads
	thread_data_t data[10];
 
 	// create mutex
 	CHECK( pthread_mutex_init(&mutex, NULL) );
 
 	// set attribute to indicate that thread is joinable
	pthread_attr_t attr;
	CHECK( pthread_attr_init(&attr) );
	CHECK( pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_JOINABLE) );
	
  	// create threads
  	for (int i=0; i<10; ++i) {
  	
    	data[i].id = i;
    	sprintf(data[i].msg, "coucou %d", 100 + rand() % 100);
    	
    	CHECK( pthread_create(&threads[i], &attr, thread_code, (void *) &data[i]) );
  	}
  	
	// destroy attribute: no necessary any more
	pthread_attr_destroy(&attr);

	// perform the join
	void *status;
	for (int i=0; i<10; ++i) {
	
  		CHECK( pthread_join(threads[i], &status) );
  		
  	}
  	
  	// this line won't be executed until all threads have terminated
  	// their execution
  	cout << "!!! END OF PROGRAM !!!!" << endl;
  	
  	// !!!!!!!!!! destroy mutex !!!!!!!!!!
  	CHECK( pthread_mutex_destroy(&mutex) );
  	
  	
  	pthread_exit(NULL);
  
  	return 0;
}