[英]Callback from Unmanaged code to managed
我正在觸發我的托管代碼並啟動對非托管代碼的調用。 非托管代碼中有回調。 從非托管我得到我的托管方法'DelegateMethod'回調。 但我沒有從非托管代碼中獲取正確的參數/參數值。 請在這件事上給予我幫助
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Runtime.InteropServices;
namespace TestApp
{
public class Program
{
public delegate void fPointer(byte[] Sendapdu, ref int Sendlen, byte[] Recvapdu, ref int Recvlen);
public struct sCommsAbstraction
{
///Function to send and receive.
public fPointer pf_TxRx;
///Other functions if necessary, e.g. reset
}
// Create a method for a delegate.
public static void DelegateMethod(byte[] Sendapdu, ref int Sendlen, byte[] Recvapdu, ref int Recvlen)
{
//This is called from unmanaged code. I am not getting proper arguments
Console.WriteLine(Sendlen);
}
[DllImport("AuthLibrary.dll", CallingConvention = CallingConvention.Cdecl)]
public static extern int CmdLib_RegisterItsIO(ref sCommsAbstraction psCommsFunctions);
[DllImport("AuthLibrary.dll", CallingConvention = CallingConvention.Cdecl)]
public static extern int CmdLib_OpenApplication();
[DllImport("TransparentChannel.dll", CallingConvention = CallingConvention.Cdecl)]
public static extern int TC_Transceive(byte[] writeBuf, ref int writeBufLen, byte[] readBuf, ref int pwReadBufferLen);
static void Main(string[] args)
{
sCommsAbstraction psCommsFunctions = new sCommsAbstraction();
// Instantiate the delegate.
psCommsFunctions.pf_TxRx = DelegateMethod;
CmdLib_RegisterItsIO(ref psCommsFunctions);
CmdLib_OpenApplication();
}
}
}
我的無限代碼存在於此處 - CmdLib.c
//C code - unmanaged
typedef int32_t (*pFTransceive)(const uint8_t *prgbWriteBuffer, const uint16_t *pwWriteBufferLen, uint8_t *prgbReadBuffer, uint16_t *pwReadBufferLen);
typedef struct sCommsAbstraction
{
///Function to send and receive.
pFTransceive pf_TxRx;
///Other functions if necessary, e.g. reset
}sCommsAbstraction_d
static sCommsAbstraction_d sCommsAbstraction = {0};
void CmdLib_RegisterItsIO(const sCommsAbstraction_d *psCommsFunctions)
{
sCommsAbstraction.pf_TxRx = psCommsFunctions->pf_TxRx;
}
void CmdLib_OpenApplication()
{
sCommsAbstraction.pf_TxRx(rgbAPDUBuffer,&wTotalLength,rgbAPDUBuffer,&psApduData->wResponseLength);
}
您的委托聲明與pFTransceive
函數指針聲明不匹配。 這會在回調方法中生成垃圾參數值。
靠近:
[UnmanagedFunctionPointer(CallingConvention.Cdecl)]
public delegate void fPointer(
[MarshalAs(UnmanagedType.LPArray, SizeParamIndex = 1)]
byte[] Sendapdu, ref short Sendlen,
[MarshalAs(UnmanagedType.LPArray, SizeParamIndex = 3)]
byte[] Recvapdu, ref short Recvlen
);
請注意必需的屬性以匹配C / C ++程序中使用的默認調用約定。 和短的參數類型匹配uint16_t
.`
更多關於在這篇文章中調用約定的奧秘。
sCommsAbstraction psCommsFunctions = new sCommsAbstraction();
這是你必須擔心的另一件事。 只要本機代碼可以進行回調,該對象就需要存活。 現在它沒有,下一個垃圾收集將破壞它,因為垃圾收集器無法找出本機代碼正在使用它。 當本機代碼進行回調時Kaboom。 你還沒有看到那個bug,調試器現在讓對象保持活着狀態。 這不會發生在生產中。
如上所述,您需要將此語句添加到Main()方法的底部:
GC.KeepAlive(psCommsFunctions);
將它存儲在靜態變量中是更好的方法,只有在您知道本機代碼不再進行回調的事實時才將其設置為null
。
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