c# - 使用指针和地址

Question

我有以下 C# 代码: (更新代码/问题) 代码和项目被标记为不安全

private struct MEMORY_BASIC_INFORMATION
        {
            internal uint BaseAddress;
            internal uint AllocationBase;
            internal uint AllocationProtect;
            internal uint RegionSize;
            internal uint State;
            internal uint Protect;
            internal uint Type;
        }


public unsafe static bool CheckForSufficientStack(long bytes)
{
    MEMORY_BASIC_INFORMATION stackInfo = new MEMORY_BASIC_INFORMATION();

    // originally was
    // IntPtr currentAddr = new IntPtr((uint)&stackInfo - 4096);

    GCHandle gh = GCHandle.Alloc(stackInfo, GCHandleType.Pinned);
    IntPtr p = gh.AddrOfPinnedObject();

    //now - this line passes compilation        
    IntPtr currentAddr = new IntPtr((uint)p - 4096);

    // build error in the below line
    VirtualQuery(currentAddr, ref stackInfo, sizeof(MEMORY_BASIC_INFORMATION));

   return ((uint)currentAddr.ToInt64() - stackInfo.AllocationBase) >
                   (bytes + STACK_RESERVED_SPACE);
}

当我编译它时，我收到错误: 无法获取托管类型的地址、获取其大小或声明指向托管类型的指针

这是我复制的代码，我实际上很惊讶地知道 C# 中有“&”，但构建失败了。

知道如何解决这个问题吗？

当我们执行 sizeof(MEMORY_BASIC_INFORMATION) 时，错误出现在最后一行

Answer 1

您必须首先将对象“固定”在内存中，以确保 GC 在您使用它时不会移动它:

GCHandle gh = GCHandle.Alloc(stackInfo, GCHandleType.Pinned);
IntPtr p = gh.AddrOfPinnedObject();

获取结构体的大小:

Marshal.SizeOf(typeof(MEMORY_BASIC_INFORMATION))