char *的一个bug？有不同顺序时产生

Thanks for your help :)

 

windows xp x86, jdk 1.6.20

 

hellojna dll project

hellojna.h

 

extern "C" _declspec(dllexport) int swapvalue(int* a, int* b);
extern "C" _declspec(dllexport) int rf_select1(unsigned char *_Size);
extern "C" _declspec(dllexport) int rf_select2(unsigned char *_Size,long icdev);
extern "C" _declspec(dllexport) int rf_select3(long icdev, unsigned char *_Size);

 

hellojna.cpp

 

#include "stdafx.h"
#include "hellojna.h"

int rf_select1(unsigned char *_Size) {
    _Size[0] = 'a';
    return 12;
}

int rf_select2(unsigned char *_Size, long icdev) {
    _Size[0] = 'a';
    return 12;
}

int rf_select3(long icdev, unsigned char *_Size) {
    _Size[0] = 'a';
    return 12;
}

HelloJna.java

 

public interface HelloJna extends Library {
	HelloJna instance = (HelloJna) Native.loadLibrary("hellojna", HelloJna.class);
	int rf_select1(byte[] abd);
	int rf_select2(byte[] abd, long dev);
	int rf_select3(long dev, byte[] abd);
}

Test.java 

public class Test {
	/**
	 * @param args
	 */
	public static void main(String[] args) {
		HelloJna jna = HelloJna.instance;

		byte[] buf = new byte[]{'s', 'u', 'p', 'e', 'r', ' ', 'm', 'a', 'n', '\0'};
		int ret = jna.rf_select1(buf);
		System.out.println("buf=" + new String(buf) + ",ret=" + ret);
		
		buf[0] = 'I';
		ret = jna.rf_select2(buf, 77);
		System.out.println("77 buf=" + new String(buf) + ",ret=" + ret);
		
		buf[0] = 'E';
		ret = jna.rf_select3(99, buf);
		System.out.println("99 buf=" + new String(buf) + ",ret=" + ret);
	}

}

console.out:

 

buf=auper man , ret=12
77 buf=auper man ,ret=12

the screen capter: 

why rf_select1 and rf_select2 is right but rf_select3 is error ??

the differences is just the paramters order??

in the rf_select3 _Size is null

 

buf[0] = 'E';
ret = jna.rf_select3(99, buf);

2010-09-15 00:13 add info:

 

I found it's work good when HelloJna.java change rf_select3(long dev, byte[] abd) to rf_select3(NativeLong dev, byte[] abd)

 

public interface HelloJna extends Library {
	HelloJna instance = (HelloJna) Native.loadLibrary("hellojna", HelloJna.class);
	int rf_select1(byte[] abd);
	int rf_select2(byte[] abd, long dev);
	int rf_select3(NativeLong dev, byte[] abd);
}

评论

2 楼 skzr.org 2012-09-05  

duduli 写道

https://github.com/twall/jna/blob/master/www/Mappings.md
官方文档上写了：long long 类型才对应java的long类型。

莫非是这个问题，看了这个映射表，long long以前好像没有这个东西，不过当时是在32位winxp下开发测试的。

1 楼 duduli 2012-09-04  

https://github.com/twall/jna/blob/master/www/Mappings.md
官方文档上写了：long long 类型才对应java的long类型。