c++方法从c#dllimport调用返回0

c++ method returning 0 from c# dllimport call

本文关键字：返回 调用 c#dllimport 方法 c++      更新时间：2023-10-16

我正在调用函数，得到的只是0，这是使用了多年的第三方软件，所以我知道它是正确的。这是c++头文件：

#ifdef __cplusplus
extern "C" {
#endif
int __stdcall initialise();
int __stdcall closedown();
int __stdcall WGS84ToLocal(double * lat, double * longt, int d);
int __stdcall LocalToWGS84(double * lat, double * longt, int d);
int __stdcall OSGB36ToOSGBGrid(double lat, double longt, double * east, double * north);
int __stdcall OSGBGridToOSGB36(double east, double north, double * lat, double * longt);

这是我的代码

  class Program
{
    public static double lon = 50.82011492;
    public static double lat = 0.117981131;
    public static double north = 50.82011492;
    public static double east = 0.117981131;
    public static Int32 OGB_M = 150;
    public static int iErr = 0;
    [DllImport("TTDatum3.Dll", EntryPoint = "WGS84ToLocal", CallingConvention = CallingConvention.StdCall, SetLastError = true)]
    public static extern Int32 WGS84ToLocal([In, Out]ref double lat, [In, Out] ref double lon, Int32 datum);
    [DllImport("TTDatum3.Dll", EntryPoint="LocalToWGS84", CallingConvention = CallingConvention.StdCall, SetLastError = true)]
    public static extern Int32 LocalToWGS84([In,Out]ref double lat,[In,Out] ref double lon, Int32 datum);
    [DllImport("TTDatum3.Dll", EntryPoint = "OSGB36ToOSGBGrid", CallingConvention = CallingConvention.StdCall, SetLastError = true)]
    public static extern Int32 OSGB36ToOSGBGrid( double lat, double lon, [In,Out] ref double east, [In,Out] ref double north);
    [DllImport("TTDatum3.Dll", EntryPoint = "OSGBGridToOSGB36", CallingConvention = CallingConvention.StdCall, SetLastError = true)]
    public static extern Int32 OSGBGridToOSGB36(double east, double north, [In,Out] ref double lat,[In,Out]  ref double lon);

    public static void Main(string[] args)
    {
       iErr = OSGBGridToOSGB36(east, north, ref lon, ref lat);
       Console.WriteLine(iErr);
       iErr = LocalToWGS84(ref lon, ref lat, OGB_M);
       Console.WriteLine(iErr);
    }

在Main中，lat和lon的顺序与上面的方法相反。不知道这是否是你问题的原因，但这只是一个输入。

你预计iErr会回来什么？请修复该部分，然后提供更新。

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