Marshal.FreeHGlobal(IntPtr) Método

public:
 static void FreeHGlobal(IntPtr hglobal);

[System.Security.SecurityCritical]
public static void FreeHGlobal(IntPtr hglobal);

public static void FreeHGlobal(IntPtr hglobal);

[<System.Security.SecurityCritical>]
static member FreeHGlobal : nativeint -> unit

static member FreeHGlobal : nativeint -> unit

Public Shared Sub FreeHGlobal (hglobal As IntPtr)

Parâmetros

Atributos

SecurityCriticalAttribute

Exemplos

O exemplo seguinte demonstra chamar o FreeHGlobal método. Este exemplo de código faz parte de um exemplo maior fornecido para a Marshal classe.

// Demonstrate how to call GlobalAlloc and
// GlobalFree using the Marshal class.
IntPtr hglobal = Marshal::AllocHGlobal(100);
Marshal::FreeHGlobal(hglobal);

// Demonstrate how to call GlobalAlloc and
// GlobalFree using the Marshal class.
IntPtr hglobal = Marshal.AllocHGlobal(100);
Marshal.FreeHGlobal(hglobal);

' Demonstrate how to call GlobalAlloc and
' GlobalFree using the Marshal class.
Dim hglobal As IntPtr = Marshal.AllocHGlobal(100)
Marshal.FreeHGlobal(hglobal)

O exemplo seguinte demonstra como converter o conteúdo de uma classe gerida String para memória não gerida e depois descartar a memória não gerida quando terminar.

using namespace System;
using namespace System::Runtime::InteropServices;

#include <iostream>                                                 // for printf


int main()
{
    // Create a managed string.
    String^ managedString = "Hello unmanaged world (from the managed world).";

    // Marshal the managed string to unmanaged memory.
    char* stringPointer = (char*) Marshal::StringToHGlobalAnsi(managedString ).ToPointer();

    printf("stringPointer = %s\n", stringPointer);

    // Always free the unmanaged string.
    Marshal::FreeHGlobal(IntPtr(stringPointer));

    return 0;
}

using System;
using System.Runtime.InteropServices;
using System.Threading;

class MainFunction
{
    static void Main()
    {
        Console.WriteLine("\nStringToGlobalAnsi\n");

        // Create a managed string.
        String  managedString = "I am a managed String";
        Console.WriteLine("1) managedString = " + managedString);

        // Marshal the managed string to unmanaged memory.
        IntPtr stringPointer = (IntPtr)Marshal.StringToHGlobalAnsi(managedString);
        Console.WriteLine("2) stringPointer = {0}", stringPointer);

        // Get the string back from unmanaged memory.
        String RetrievedString = Marshal.PtrToStringAnsi(stringPointer);
        Console.WriteLine("3) Retrieved from unmanaged memory = " + RetrievedString);

        // Always free the unmanaged string.
        Marshal.FreeHGlobal(stringPointer);

        // IntPtr handle value is still the same:
        Console.WriteLine("4) stringPointer = " + stringPointer);

        // However, the data may be cleared after the memory is freed, depending on whether the memory allocated to stringPointer
        // has been reclaimed or not. Uncommenting the following line (Thread.Sleep(1000)) increases the likelihood of the memory being reclaimed.
        // Thread.Sleep(1000);
        String RetrievedString2 = Marshal.PtrToStringAnsi(stringPointer);
        Console.WriteLine("5) RetrievedString2 = " + RetrievedString2);
    }
}

Observações

Pode usar FreeHGlobal para libertar qualquer memória do heap global alocado por AllocHGlobal, ReAllocHGlobal, ou qualquer método equivalente de API não gerida. Se o hglobal parâmetro for IntPtr.Zero o método não faz nada.

FreeHGlobal expõe a função LocalFree de Kernel32.DLL, que liberta todos os bytes para que já não possa usar a memória apontada por hglobal.

Além de FreeHGlobal, a Marshal classe fornece dois outros métodos de API de desalocação de memória: DestroyStructure e FreeCoTaskMem.

Ver também

• AllocHGlobal(IntPtr)
• ReAllocHGlobal(IntPtr, IntPtr)