more attempts at wait

example-go-channel/sendFunction.go

@@ -4,13 +4,10 @@
 package main
 
 import (
-	"fmt"
+	"log"
 	"sync"
 )
 
-var wg sync.WaitGroup
-var functionChan chan func (*sync.WaitGroup)
-
 type funcWait struct {
 	f func()
 	wgF sync.WaitGroup
@@ -18,41 +15,52 @@ type funcWait struct {
 	res int
 }
 
+var functionChan chan *funcWait
+var afunc funcWait
+var wg sync.WaitGroup
 
-func generateNumbers(total int, ch chan<- func (), wg *sync.WaitGroup) {
+func generateNumbers(total int, ch chan<- *funcWait, af *funcWait) {
 	defer wg.Done()
 
-	fmt.Printf("sending %d to channel\n", total)
+	log.Println("generateNumbers() START total =", total)
-	ch <- func() {
+	ch <- af
-		fmt.Printf("inside f() sending %d to channel\n", total)
+	log.Println("generateNumbers() END total =", total)
-	}
 }
 
-func andlabsGoroutine(ch <-chan func(), wg *sync.WaitGroup) {
+func andlabsGoroutine(ch <-chan *funcWait, wgF *sync.WaitGroup) {
 	defer wg.Done()
 
+	log.Println("andlabsGoroutine() START")
 	for f := range ch {
-		fmt.Printf("read f() from channel\n")
+		log.Println("read f() from channel")
-		f()
+		f.f()
 	}
+	log.Printf("andlabsGoroutine() END")
 }
 
 func main() {
-	functionChan = make(chan func(*sync.WaitGroup))
 
-	r := make(chan func() (int, error))
+	functionChan = make(chan *funcWait)
-	res, err = (<-r)()
+
+	// syntax to get the return values from a channel
+//	r := make(chan func() (int, error))
+//	afunc.res, afunc.err = (<-r)()
 
 	wg.Add(1)
 	go andlabsGoroutine(functionChan, &wg)
 
-	for idx := 1; idx <= total; idx++ {
+	afunc.wgF = wg
-		generateNumbers(idx, functionChan, &wg)
+	afunc.f = func() {
+		log.Println("\tGOT INSIDE: running f() from inside the structure & inside the wait group goroutine")
+	}
+
+	for idx := 1; idx <= 10; idx++ {
+		generateNumbers(idx, functionChan, &afunc)
 	}
 
 	close(functionChan)
 
-	fmt.Println("Waiting for goroutines to finish...")
+	log.Println("Waiting for goroutines to finish...")
 	wg.Wait()
-	fmt.Println("Done!")
+	log.Println("Done!")
 }