/*
 * 	 	              Exemple "ForkJoin.c" PVM versio 3.3
 *			 Susana Maria Bajo Sanchez (ei05646@salleURL.edu)
 *			 Josep Maria Garrell i Guiu (josepmg@salleURL.edu)
 *					Software Paral·lel
 *		              Departament d'Informatica (DI)
 *	                 Enginyeria i Arquitectura La Salle
 *		              Universitat Ramon Llull (URL)
 * 			              Curs 1999/2000
*/

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "pvm3.h"

#define MAXNCHILD 20	// Maximum number of children this program will spawn
#define JOINTAG 11 	// Tag to use for the joing message

//----------------------------------------------------------------------
int main(int argc, char* argv[]) 
{
int ntask = 3; 			// # of tasks to spawn, use 3 as the default
int info; 				// return code from pvm calls
int mytid;				// my task id
int myparent; 			// my parents task id
int child[MAXNCHILD]; 		// children task id array 
int i, mydata, buf, len, tag, tid; 

	// find out my task id number
	mytid = pvm_mytid(); 

	// check for error
	if (mytid<0) 
		{
		pvm_perror(argv[0]); 		// print out the error
		return -1; 				// exit the program
		}
 
	// find my parent's task id number
	myparent = pvm_parent(); 

	// exit if there is some error other than PvmNoParent
	if ((myparent<0) && (myparent!=PvmNoParent))
		{
		pvm_perror(argv[0]); 
		pvm_exit(); 
		return -1; 
		} 

	// if i don't have a parent then i am the parent
	if (myparent == PvmNoParent)
		{
		// find out how many tasks to spawn
		if (argc == 2) ntask = atoi(argv[1]); 

		// make sure ntask is legal
		if ((ntask < 1) || (ntask > MAXNCHILD)) { pvm_exit(); return 0; }

		// spawn the child tasks 
		info = pvm_spawn(argv[0],(char**)0,PvmTaskDefault,(char*)0,ntask,child); 
		
		// print out the task ids
		for (i=0; i<ntask;i++) 
			if (child[i] < 0) printf(" %d", child[i]);  // print the error code
				else printf("t%x\t", child[i]); // print the task id

		putchar('\n'); 

		// make sure spawn succeeded 
		if (info == 0) { pvm_exit(); return -1;}

		// only expect responses from those spawned correctly
		ntask = info; 
		for (i=0;i<ntask;i++)
			{
			// recv a message from any child process
			buf = pvm_recv(-1, JOINTAG); 
			if (buf < 0) pvm_perror("calling recv"); 

			info = pvm_bufinfo(buf, &len, &tag, &tid); 
			if (info < 0) pvm_perror("calling pvm_bufinfo"); 

			info = pvm_upkint(&mydata, 1, 1); 
			if (info < 0) pvm_perror("calling pvm_upkint"); 

			if (mydata != tid) printf("This should not happen!\n"); 
			printf("Length %d, Tag %d, Tid t%x\n", len, tag, tid); 
			} 

		pvm_exit(); 
		return 0; 
		}
 
	// i'm a child
	info = pvm_initsend(PvmDataDefault); 
	if (info < 0)
		{
		pvm_perror("calling pvm_initsend"); 
		pvm_exit();
		return -1; 
		} 
	
	info = pvm_pkint(&mytid, 1, 1); 
	if (info < 0)
		{
		pvm_perror("calling pvm_pkint"); 
		pvm_exit();
		return -1; 
		} 
	
	info = pvm_send(myparent, JOINTAG); 
	if (info < 0)
		{
		pvm_perror("calling pvm_send");
		pvm_exit(); 
		return -1; 
		} 

	pvm_exit(); 
	return 0;
}