Crash in simple producer/consumer program #14
Description
The program below crashes:
// This is a simple producer/consumer system.
package main
import (
"fmt"
"math/rand"
"time"
. "github.com/pspaces/gospace"
)
// PRODUCERS defines the number of producers.
const PRODUCERS = 2
// NTASKS defines the number of tasks each producer generates.
const NTASKS = 2
// WORKERS defines the number of workers.
const WORKERS = 2
func main() {
rand.Seed(time.Now().UTC().UnixNano())
bag := NewSpace("bag")
for i := 0; i < PRODUCERS; i++ {
go producer(&bag, i, NTASKS)
}
for i := 0; i < WORKERS; i++ {
go worker(&bag, i)
}
bag.Query("done")
}
func producer(bag *Space, me int, ntasks int) {
for i := 0; i < ntasks; i++ {
x := rand.Intn(10)
bag.Put(x)
fmt.Printf("Producer %d added %d to the bag...\n", me, x)
}
}
func worker(bag *Space, me int) {
var x int
var y int
for {
// Get one number.
bag.Get(&x)
// Try to get another number.
_, err := bag.GetP(&y)
if err == nil {
// If found then reduce.
fmt.Printf("Worker %d got pair (%d,%d) to reduce.\n", me, x, y)
x = x + y
bag.Put(x)
fmt.Printf("Worker %d added %d to the bag.\n", me, x)
} else {
// If not found, replace the first number.
bag.Put(x)
}
}
}