我正在尝试使用互操作调用来获取C＃中命名管道客户端的进程ID和计算机名称：

[DllImport("kernel32.dll",SetLastError = true)]
internal static extern bool GetNamedPipeclientProcessId(IntPtr Pipe,out uint ClientProcessId);

private static uint getclientProcessID(NamedPipeServerStream pipeServer)
{
    uint processId;
    IntPtr pipeHandle = pipeServer.SafePipeHandle.DangerousGetHandle();
    if (GetNamedPipeclientProcessId(pipeHandle,out processId))
    {
        return processId;
    }
    return 0;
}

[DllImport("kernel32.dll",SetLastError = true)]
internal static extern bool GetNamedPipeclientComputerName(IntPtr Pipe,out string ClientComputerName,uint ClientComputerNameLength);

private static string getclientComputerName(NamedPipeServerStream pipeServer)
{
    string computerName;
    uint buffer = 32768;
    IntPtr pipeHandle = pipeServer.SafePipeHandle.DangerousGetHandle();
    if (GetNamedPipeclientComputerName(pipeHandle,out computerName,buffer))
    {
        return computerName;
    }
    return null;
}

GetNamedPipeclientProcessId调用正在工作，但是GetNamedPipeclientComputerName返回false。是什么导致那个失败？