Windows CE 上 GlobalMemoryStatusEx 的 PInvoke

Question

如果您不从事或不了解 Windows CE 和 Compact Framework，请不要投反对票。谢谢

有人知道这个函数在 WinCE 上是否可用吗？（如果是的话）DLL 是什么？我已尝试从 "coredll.dll" 和 "kernel.dll" 调用 PInvoke。 Win32版本来自"kernel32.dll".

[return: MarshalAs(UnmanagedType.Bool)]
[DllImport("kernel.dll")] // and "coredll.dll" also doesn't work
public static extern bool GlobalMemoryStatusEx([In,Out] MEMORYSTATUSEX lpBuffer);

当我尝试使用上述函数时出现异常 "Can't find PInvoke DLL 'kernel.dll'."

PS：我使用了大量的 PInvoked 函数，比如这个：

[DllImport("coredll.dll")]
public static extern IntPtr SendMessage(IntPtr hWnd, int nMsg, IntPtr wParam, IntPtr lParam);

Answer 1

只有GlobalMemoryStatus call, not the extended (...Ex) version. It is located in coredll.dll, see http://pinvoke.net/default.aspx/coredll.GlobalMemoryStatus

Answer 2

已实施 C.Evenhuis 建议的答案并且效果很好。这是供将来可能需要此代码的人使用的代码：

// Structure to allow getting memory usage
public struct MEMORYSTATUS
{
        public int nLength;
        public int nMemoryLoad;
        public uint uTotalPhys;
        public uint uAvailPhys;
        public uint uTotalPageFile;
        public uint uAvailPageFile;
        public uint uTotalVirtual;
        public uint uAvailVirtual;
}

[DllImport("coredll", EntryPoint="GlobalMemoryStatus", SetLastError = false)]
public static extern void GlobalMemoryStatus(out MEMORYSTATUS memCE);

MEMORYSTATUS mem = new MEMORYSTATUS();
mem.nLength = Marshal.SizeOf(typeof(MEMORYSTATUS));
GlobalMemoryStatus(out mem);
// Label1.Text = (mem.uAvailPhys.ToString() + "Bytes");

Answer 3

我是这样用的

/// <summary>
/// https://msdn.microsoft.com/en-us/library/ee488368.aspx
/// This structure contains information about current memory availability. The GlobalMemoryStatus function uses this structure.
/// </summary>
[StructLayout(LayoutKind.Sequential)]
public struct MemoryStatus
{
    /// <summary>
    /// Specifies the size, in bytes, of the MEMORYSTATUS structure.
    /// Set this member to sizeof(MEMORYSTATUS) when passing it to the GlobalMemoryStatus function.
    /// </summary>
    public int Length;
    /// <summary>
    /// Specifies a number between zero and 100 that gives a general idea of current memory use, in which zero indicates no memory use and 100 indicates full memory use.
    /// </summary>
    public uint MemoryLoad;
    /// <summary>
    /// Indicates the total number of bytes of physical memory.
    /// </summary>
    public uint TotalPhys;
    /// <summary>
    /// Indicates the number of bytes of physical memory available.
    /// </summary>
    public uint AvailPhys;
    /// <summary>
    /// Indicates the total number of bytes that can be stored in the paging file.
    /// This number does not represent the physical size of the paging file on disk.
    /// </summary>
    public uint TotalPageFile;
    /// <summary>
    /// Indicates the number of bytes available in the paging file.
    /// </summary>
    public uint AvailPageFile;
    /// <summary>
    /// Indicates the total number of bytes that can be described in the user mode portion of the virtual address space of the calling process.
    /// </summary>
    public uint TotalVirtual;
    /// <summary>
    /// Indicates the number of bytes of unreserved and uncommitted memory in the user mode portion of the virtual address space of the calling process.
    /// </summary>
    public uint AvailVirtual;
    [DllImport("coredll.dll")]
    private static extern void GlobalMemoryStatus(ref MemoryStatus ms);
    public static string GetMemoryStatus()
    {
        var retValue = new StringBuilder();
        MemoryStatus ms = GlobalMemoryStatus();
        retValue.AppendLine(string.Format("Memory Load {0} %", ms.MemoryLoad));
        retValue.AppendLine(string.Format("Total Phys {0} Kb", ms.TotalPhys / 1024));
        retValue.AppendLine(string.Format("Avail Phys {0} Kb", ms.AvailPhys / 1024));
        retValue.AppendLine(string.Format("Tota PFile {0} bytes", ms.TotalPageFile));
        retValue.AppendLine(string.Format("Avai PFile {0} bytes", ms.AvailPageFile));
        retValue.AppendLine(string.Format("Total Virt {0} Kb", ms.TotalVirtual / 1024));
        retValue.AppendLine(string.Format("Avail Virt {0} Kb", ms.AvailVirtual / 1024));
        return retValue.ToString();
    }

    public static MemoryStatus GlobalMemoryStatus()
    {
        MemoryStatus ms = new MemoryStatus();
        ms.Length = Marshal.SizeOf(ms);
        GlobalMemoryStatus(ref ms);
        return ms;
    }
    public static uint GetMemoryLoad()
    {
        var ms = GlobalMemoryStatus();
        return ms.MemoryLoad;
    }
}

您可以签入 Windows CE SDKWinBase.h

typedef struct _MEMORYSTATUS {
    DWORD dwLength;
    DWORD dwMemoryLoad;
    DWORD dwTotalPhys;
    DWORD dwAvailPhys;
    DWORD dwTotalPageFile;
    DWORD dwAvailPageFile;
    DWORD dwTotalVirtual;
    DWORD dwAvailVirtual;
} MEMORYSTATUS, *LPMEMORYSTATUS;

VOID
WINAPI
GlobalMemoryStatus(
    __inout LPMEMORYSTATUS lpBuffer
    );

因为在SDK中是_inout。我使用了“ref”参数修饰符。

这就是全部。

Windows CE 上 GlobalMemoryStatusEx 的 PInvoke

PInvoke for GlobalMemoryStatusEx on Windows CE

c#

compact-framework

windows-ce