reflect.Close() Function in Golang with Examples

Last Updated : 03 May, 2020

Go language provides inbuilt support implementation of run-time reflection and allowing a program to manipulate objects with arbitrary types with the help of reflect package. The reflect.Close() Function in Golang is used to close the channel v. To access this function, one needs to imports the reflect package in the program.

Syntax:
func (v Value) Close()
Parameters: This function does not accept any parameters.

Return Value: This function does not return any value.

Below examples illustrate the use of the above method in Golang:

Example 1:

// Golang program to illustrate  
// reflect.Close() Function  
  
package main 
   
 import ( 
    "fmt"
    "reflect"
 ) 
   
type T int
  
func IsClosed(ch <-chan T) bool { 
    select { 
    case <-ch: 
        return true
    default: 
    } 
  
    return false
} 
  
func main() { 
    c := make(chan T) 
    vc := reflect.ValueOf(c) 
    fmt.Println(IsClosed(c)) 
      
    // use of Close() method 
    vc.Close() 
    fmt.Println(IsClosed(c)) 
}                     

Output:

false
true

Example 2:

// Golang program to illustrate  
// reflect.Close() Function  
  
package main 
   
 import ( 
    "fmt"
    "reflect"
 ) 
   
func main() { 
    c := make(chan int, 1) 
    vc := reflect.ValueOf(c) 
    succeeded := vc.TrySend(reflect.ValueOf(123)) 
    fmt.Println(succeeded, vc.Len(), vc.Cap()) 
   
    vSend, vZero := reflect.ValueOf(789), reflect.Value{} 
    branches := []reflect.SelectCase{ 
        {Dir: reflect.SelectDefault, Chan: vZero, Send: vZero}, 
        {Dir: reflect.SelectRecv, Chan: vc, Send: vZero}, 
        {Dir: reflect.SelectSend, Chan: vc, Send: vSend}, 
    } 
       
    selIndex, vRecv, sentBeforeClosed := reflect.Select(branches) 
    fmt.Println(selIndex)        
    fmt.Println(sentBeforeClosed) 
    fmt.Println(vRecv.Int())    
  
    // use of Close() method 
    vc.Close() 
   
}        

Output:

true 1 1
1
true
123

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