在尝试通过JNA回调从C ++应用程序获取通知时,我经常看到JVM崩溃。 Native.setProtected没有帮助。原始回调声明是
typedef void (__stdcall *TRANS2QUIK_ORDER_STATUS_CALLBACK) (long nMode, DWORD dwTransID, double dNumber, LPCSTR ClassCode, LPCSTR SecCode, double dPrice, long nBalance, double dValue, long nIsSell, long nStatus, long nOrderDescriptor);
^^^这是行不通的
我尝试了应该工作的StdCallLibrary.StdCallCallback和简单的Callback,它们都失败了。 但在我编写C ++包装器之后,我只是从原始C ++ stdcall回调中调用JNA回调作为cdecl,一切都开始顺利进行。
typedef void (*WRAPPED_ORDER_STATUS_CALLBACK) (double dNumber, double dPrice, long nBalance, double dValue, long nIsSell, long nStatus, long nOrderDescriptor);
QUIKWRAP_API TRANS2QUIK_ORDER_STATUS_CALLBACK __stdcall wrapCallback(WRAPPED_ORDER_STATUS_CALLBACK);
^^^^^^这是没有问题的顺利工作
这个问题可能是专门针对此功能签名的JNA错误吗? 因为我的代码中有另一个带有不同签名的stdcall回调,它运行得很好。
我为此问题创建了一个独立的测试用例,见下文: java
import java.util.HashMap;
import com.sun.jna.Library;
import com.sun.jna.Native;
import com.sun.jna.NativeLong;
import com.sun.jna.Pointer;
import com.sun.jna.PointerType;
import com.sun.jna.platform.win32.WinDef;
import com.sun.jna.platform.win32.WinDef.DWORD;
import com.sun.jna.win32.StdCallLibrary;
public class JNATest {
interface TestCallback extends StdCallLibrary.StdCallCallback {
void testCallback(NativeLong nMode, WinDef.DWORD dwTransID, double dNumber, LPCSTR ClassCode, LPCSTR SecCode, double dPrice, NativeLong nBalance, double dValue, NativeLong nIsSell, NativeLong nStatus, NativeLong nOrderDescriptor);
}
interface JNADLL extends StdCallLibrary{
void testCallback(TestCallback cb);
}
public static class LPCSTR extends PointerType {
public LPCSTR(Pointer address) {
super(address);
}
public LPCSTR() {
super();
}
@Override
public String toString() {
return getPointer().getString(0);
}
};
/**
* @param args
*/
public static void main(String[] args) {
System.setProperty("jna.encoding", "Cp1251");
HashMap<String, Object> nameMapping = new HashMap<String, Object>();
nameMapping.put(Library.OPTION_FUNCTION_MAPPER, StdCallLibrary.FUNCTION_MAPPER);
nameMapping.put(Library.OPTION_CALLING_CONVENTION, StdCallLibrary.STDCALL_CONVENTION);
JNADLL JNADll = (JNADLL) Native.loadLibrary("QuikWrap", JNADLL.class, nameMapping);
TestCallback cb = new TestCallback() {
@Override
public void testCallback(NativeLong nMode, DWORD dwTransID,
double dNumber, JNATest.LPCSTR ClassCode, JNATest.LPCSTR SecCode,
double dPrice, NativeLong nBalance, double dValue,
NativeLong nIsSell, NativeLong nStatus, NativeLong nOrderDescriptor) {
System.out.println("testCallback \n" +
" nMode: " + nMode + "\n" +
" dwTransID: " + dwTransID + "\n" +
" number: " + dNumber + "\n" +
" ClassCode: " + ClassCode + "\n" +
" SecCode: " + SecCode + "\n" +
" price: " + dPrice + "\n" +
" balance: " + nBalance + "\n" +
" value: " + dValue + "\n" +
" isSell: " + nIsSell + "\n" +
" status: " + nStatus + "\n" +
" orderDescriptor: " + nOrderDescriptor + "\n");
}
};
JNADll.testCallback(cb);
}
}
c标题QuikWrap.h
#ifdef QUIKWRAP_EXPORTS
#define QUIKWRAP_API extern "C"__declspec(dllexport)
#else
#define QUIKWRAP_API __declspec(dllimport)
#endif
typedef void (__stdcall *TRANS2QUIK_ORDER_STATUS_CALLBACK) (long nMode, DWORD dwTransID, double dNumber, LPCSTR ClassCode, LPCSTR SecCode, double dPrice, long nBalance, double dValue, long nIsSell, long nStatus, long nOrderDescriptor);
QUIKWRAP_API void __stdcall testCallback(TRANS2QUIK_ORDER_STATUS_CALLBACK cb);
c来源QuikWrap.cpp
#include "stdafx.h"
#include "QuikWrap.h"
#include "stdio.h"
QUIKWRAP_API void __stdcall testCallback(TRANS2QUIK_ORDER_STATUS_CALLBACK cb){
cb(1, 2, 3, "Hi", "Bye", 4.0, 5, 6, 7, 8, 9);
cb(0, 2, 3, "Hi", "Bye", 4.0, 5, 6, 7, 8, 9);
return;
}
我收到的唯一回调输出是
testCallback
nMode: 1
dwTransID: 2
number: 3.0
ClassCode: Hi
SecCode: Bye
price: 4.0
balance: 5
value: 6.0
isSell: 7
status: 8
orderDescriptor: 9
然后退出时回调失败
答案 0 :(得分:2)
问题是由于libffi
中的错误,其中堆栈对齐正在根据参数大小进行调整,这是stdcall
的错误行为。