A collection of files related to producer consumer programming models.

requester.c

#include <sys/errno.h>
#include <sys/types.h>
#include <sys/ipc.h>
#include <sys/msg.h>
#include <stdio.h>
#include <stdlib.h>
#include <time.h>

//removed by doug
//#include "message.h"

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

	// Memory structure to represent message in queue
	struct {
		long priority;
		int number;
	} msgp;


	int msqid,status; 	// id for receive queue and status
	int qidSupplier; 	// id for send queue plus key for getting queues
	int i, random_number; 	// incremental variable and placeholder from random

	// Instantiate queue item
	msgp.priority= 2;
	msgp.number = 0;

	// Let's seed the random number generator with the clock
	srand(time(NULL));
	
	// Add key variables
	int msqid_key, qidSupplier_key;

	// get a key based on pwd directory R byte
	msqid_key = ftok(".", 'S');
	
	// Negative result is error
	if (msqid_key < 0)
		perror("Unable to create msqid_key\n");

	// get a key based on pwd directory and S byte
	qidSupplier_key = ftok(".", 'R');

	// Negative result is error
	if ( qidSupplier_key < 0)
		perror("Unable to create qidSuppler_key\n");

	//~ Create a Q for receiving information (you can use 
	//~ the variable key as the unique identifier)
	msqid = msgget( msqid_key, 0660 | IPC_CREAT);

	//~ Create a Q for sending information to the supplier 
	//~ (you can use key+1 as the unique identifier)
	qidSupplier = msgget( qidSupplier_key, 0660 | IPC_CREAT);

	//~ Loop 100 times
	for ( i = 0; i < 100; i++ ) {

		//~ Generate a random number (between 0 and 500)
		//
		random_number = rand() % 500; 	// In order to pair a base n and response n^2 we save n
		msgp.number = random_number;	// Set queue item equal to random number

		//~ Send the number to the supplier
		status = msgsnd( qidSupplier, &msgp, sizeof(msgp)-sizeof(long), 0);
		
		if ( status >= 0 ) {
			//~ Receive the answer back from the supplier
			status = msgrcv(msqid, &msgp, sizeof(msgp)-sizeof(long), 2, 0);

			if (status >= 0) {
				//~ Display the solution to the console
				printf("%i**2 = %i\n", random_number, msgp.number);

				if ( ( random_number * random_number ) != msgp.number ) {
					printf("Error: recived value (%i) is not square of sent value(%i).\n", msgp.number, i);
					return -1;
				}
			} else {
				printf("Error receiving response from supplier.\n");
				return -1;
			}
		} else {
			printf("Error sending number to supplier(%i).\n", status);
			return -1;
		}
	}

	printf("all done\n");
	return(0);

}

supplier.c

#include <stdio.h>
#include <sys/errno.h>
#include <sys/types.h>
#include <sys/ipc.h>
#include <sys/msg.h>
#include <stdlib.h>


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

	// Memory structure to represent message in queue
	struct {
		long priority;
		int number;
	} msgp;

	// Instantiate queue item
	msgp.priority= 2;
	msgp.number = 0;

	int msqid; 		// key for recieve queue
	int supplierQid;	// key for send qeueu
	int status;		// placeholder for status
	
	// Add key variables
	int msqid_key, qidSupplier_key;

	// get a key based on pwd directory R byte
	msqid_key = ftok(".", 'R');
	
	// Negative result is error
	if (msqid_key < 0)
		perror("Unable to create msqid_key\n");

	// get a key based on pwd directory and S byte
	qidSupplier_key = ftok(".", 'S');

	// Negative result is error
	if ( qidSupplier_key < 0)
		perror("Unable to create qidSuppler_key\n");

	//~ Create a Q for receiving information (you can use key
	//~ as unique identifier)
	msqid = msgget( msqid_key, 0660 | IPC_CREAT);

	//~ Create a Q for sending information to the requester
	//~ (you can use key-1 as the unique identifier)
	supplierQid = msgget( qidSupplier_key, 0660 | IPC_CREAT);

	//~ Loop
	while ( 1 ) {

		//~ Receive number from requester
		status = msgrcv(msqid ,&msgp,sizeof(msgp)-sizeof(long),2,0);
		
		if ( status >= 0 ) {
			//~ Calculate square of that number
			msgp.number = msgp.number * msgp.number;

			//~ Send that calculated number back to the requester    
			status = msgsnd( supplierQid, &msgp, sizeof(msgp)-sizeof(long), 0);

			if ( status ) {
				printf("Error sending message to requester.\n");
				return -1;
			}
		} else {
			printf("Error receiving message from requester.\n");
			return -1;
		}
	}

	return 0;
}

test.go

package main

import "fmt"

func main() {
	fmt.Printf("Hello, world!")
}

You can see I used the ftok(char* path, char key) to get id's relavtive to the execution path of the program. This way there is no collisions.