GC.MaxGeneration Property
Definition
Important
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Gets the maximum number of generations that the system currently supports.
public:
static property int MaxGeneration { int get(); };public static int MaxGeneration { get; }static member MaxGeneration : intPublic Shared ReadOnly Property MaxGeneration As IntegerProperty Value
A value that ranges from zero to the maximum number of supported generations.
Examples
The following example demonstrates how to use the MaxGeneration property to display the largest generation number currently in use.
using namespace System;
const long maxGarbage = 1000;
ref class MyGCCollectClass
{
public:
void MakeSomeGarbage()
{
Version^ vt;
for ( int i = 0; i < maxGarbage; i++ )
{
// Create objects and release them to fill up memory
// with unused objects.
vt = gcnew Version;
}
}
};
int main()
{
MyGCCollectClass^ myGCCol = gcnew MyGCCollectClass;
// Determine the maximum number of generations the system
// garbage collector currently supports.
Console::WriteLine( "The highest generation is {0}", GC::MaxGeneration );
myGCCol->MakeSomeGarbage();
// Determine which generation myGCCol object is stored in.
Console::WriteLine( "Generation: {0}", GC::GetGeneration( myGCCol ) );
// Determine the best available approximation of the number
// of bytes currently allocated in managed memory.
Console::WriteLine( "Total Memory: {0}", GC::GetTotalMemory( false ) );
// Perform a collection of generation 0 only.
GC::Collect( 0 );
// Determine which generation myGCCol object is stored in.
Console::WriteLine( "Generation: {0}", GC::GetGeneration( myGCCol ) );
Console::WriteLine( "Total Memory: {0}", GC::GetTotalMemory( false ) );
// Perform a collection of all generations up to and including 2.
GC::Collect( 2 );
// Determine which generation myGCCol object is stored in.
Console::WriteLine( "Generation: {0}", GC::GetGeneration( myGCCol ) );
Console::WriteLine( "Total Memory: {0}", GC::GetTotalMemory( false ) );
}
using System;
namespace GCCollectIntExample
{
class MyGCCollectClass
{
private const long maxGarbage = 1000;
static void Main()
{
MyGCCollectClass myGCCol = new MyGCCollectClass();
// Determine the maximum number of generations the system
// garbage collector currently supports.
Console.WriteLine("The highest generation is {0}", GC.MaxGeneration);
myGCCol.MakeSomeGarbage();
// Determine which generation myGCCol object is stored in.
Console.WriteLine("Generation: {0}", GC.GetGeneration(myGCCol));
// Determine the best available approximation of the number
// of bytes currently allocated in managed memory.
Console.WriteLine("Total Memory: {0}", GC.GetTotalMemory(false));
// Perform a collection of generation 0 only.
GC.Collect(0);
// Determine which generation myGCCol object is stored in.
Console.WriteLine("Generation: {0}", GC.GetGeneration(myGCCol));
Console.WriteLine("Total Memory: {0}", GC.GetTotalMemory(false));
// Perform a collection of all generations up to and including 2.
GC.Collect(2);
// Determine which generation myGCCol object is stored in.
Console.WriteLine("Generation: {0}", GC.GetGeneration(myGCCol));
Console.WriteLine("Total Memory: {0}", GC.GetTotalMemory(false));
Console.Read();
}
void MakeSomeGarbage()
{
Version vt;
for(int i = 0; i < maxGarbage; i++)
{
// Create objects and release them to fill up memory
// with unused objects.
vt = new Version();
}
}
}
}
open System
let maxGarbage = 1000
type MyGCCollectClass() =
member _.MakeSomeGarbage() =
for _ = 1 to maxGarbage do
// Create objects and release them to fill up memory with unused objects.
Version() |> ignore
[<EntryPoint>]
let main _ =
let myGCCol = MyGCCollectClass()
// Determine the maximum number of generations the system
// garbage collector currently supports.
printfn $"The highest generation is {GC.MaxGeneration}"
myGCCol.MakeSomeGarbage()
// Determine which generation myGCCol object is stored in.
printfn $"Generation: {GC.GetGeneration myGCCol}"
// Determine the best available approximation of the number
// of bytes currently allocated in managed memory.
printfn $"Total Memory: {GC.GetTotalMemory false}"
// Perform a collection of generation 0 only.
GC.Collect 0
// Determine which generation myGCCol object is stored in.
printfn $"Generation: {GC.GetGeneration myGCCol}"
printfn $"Total Memory: {GC.GetTotalMemory false}"
// Perform a collection of all generations up to and including 2.
GC.Collect 2
// Determine which generation myGCCol object is stored in.
printfn $"Generation: {GC.GetGeneration myGCCol}"
printfn $"Total Memory: {GC.GetTotalMemory false}"
0
Namespace GCCollectInt_Example
Class MyGCCollectClass
Private maxGarbage As Long = 10000
Public Shared Sub Main()
Dim myGCCol As New MyGCCollectClass
'Determine the maximum number of generations the system
'garbage collector currently supports.
Console.WriteLine("The highest generation is {0}", GC.MaxGeneration)
myGCCol.MakeSomeGarbage()
'Determine which generation myGCCol object is stored in.
Console.WriteLine("Generation: {0}", GC.GetGeneration(myGCCol))
'Determine the best available approximation of the number
'of bytes currently allocated in managed memory.
Console.WriteLine("Total Memory: {0}", GC.GetTotalMemory(False))
'Perform a collection of generation 0 only.
GC.Collect(0)
'Determine which generation myGCCol object is stored in.
Console.WriteLine("Generation: {0}", GC.GetGeneration(myGCCol))
Console.WriteLine("Total Memory: {0}", GC.GetTotalMemory(False))
'Perform a collection of all generations up to and including 2.
GC.Collect(2)
'Determine which generation myGCCol object is stored in.
Console.WriteLine("Generation: {0}", GC.GetGeneration(myGCCol))
Console.WriteLine("Total Memory: {0}", GC.GetTotalMemory(False))
Console.Read()
End Sub
Sub MakeSomeGarbage()
Dim vt As Version
Dim i As Integer
For i = 0 To maxGarbage - 1
'Create objects and release them to fill up memory
'with unused objects.
vt = New Version
Next i
End Sub
End Class
End Namespace
Remarks
The generation number, or age, of an object is an implementation-defined relative measure of an object's lifespan. The most recently created objects are in generation 0 and the oldest objects are in a generation less than or equal to the generation returned by the MaxGeneration property.
The garbage collector assumes that newer memory is more likely to be eligible for garbage collection than older memory. Therefore, the garbage collector improves its performance by adjusting generation numbers each time it reclaims memory, and the MaxGeneration property value can grow over time.
If object aging is implemented, the MaxGeneration property returns the maximum generation number used by the system; otherwise, this property returns zero.
For this implementation, the value returned by the MaxGeneration property is guaranteed to remain constant for the lifetime of an executing application.
Use the MaxGeneration property to determine the maximum value you can specify when calling the Collect(Int32) method that takes a generation parameter.
