Java 使用Swig&;函数指针回调出现问题
我们在java中加载的一个库中有一个C函数,它接受一个函数指针 功能定义如下Java 使用Swig&;函数指针回调出现问题,java,c,java-native-interface,function-pointers,swig,Java,C,Java Native Interface,Function Pointers,Swig,我们在java中加载的一个库中有一个C函数,它接受一个函数指针 功能定义如下 typedef char int8 typedef unsigned short uint16 uint32 poll_broadcasts(void *(pfn)(int8*,uint16)); 在C语言中,它的用法如下 void handle_broadcasts( int8 *broadcast, uint16 length ) uint32 a = poll_broadcasts( (void*(*)(i
typedef char int8
typedef unsigned short uint16
uint32 poll_broadcasts(void *(pfn)(int8*,uint16));
在C语言中,它的用法如下
void handle_broadcasts( int8 *broadcast, uint16 length )
uint32 a = poll_broadcasts( (void*(*)(int8*,uint16)) handle_broadcasts )
但当您使用Swig生成JNI包装器时,它会为poll\u广播创建以下定义
public static long poll_broadcasts(SWIGTYPE_p_f_p_char_unsigned_short__p_void pfn) {
return TestJNI.poll_broadcasts(SWIGTYPE_p_f_p_char_unsigned_short__p_void.getCPtr(pfn));
}
根据在下面试用 测试h Swig接口文件Test.i 实现接口 最后使用时 并没有编译错误,但当程序运行并且poll_broadcasts调用从java传递的句柄广播函数指针(在C中)时,它会崩溃,出现异常访问冲突 看起来它与函数的int8*arg有关,但无法理解
有人请帮忙。当你播放
uint32民意测验时(void*(pfn)(int8*,uint16))代码>,您是指函数指针吗?如果是,则应改为uint32 poll_广播(void(*pfn)(int8*,uint16))代码>是,它是一个接受函数指针作为参数的函数。我想通过一个java方法回调来使用JNI轮询broacast。我们不能修改poll_广播。在回答帖子中提到的问题时取得了一些成功,但运气不好,程序在运行时崩溃。typedef void*(*callback\u handle\u broadcast)(int8*,uint16)代码>:您是否希望函数的返回类型为void
或void*
?最初尝试使用void,但定义与Swig创建的定义不匹配。根据轮询广播定义,java回调必须映射到typedef void*(*callback\u handle\u broadcast)(int8*,uint16)
。在C语言中,虽然它的工作方式与我写的一样,poll\u广播((void*(*)(int8*,uint16))handle\u广播)
它调用handle\u广播函数,并且它有返回类型void
。您有数据的定义吗?您正在set\u handle\u broadcast
中访问它,但我似乎在任何地方都找不到它的定义?
void * data;
typedef void* (*callback_handle_broadcast_t)(int8*, uint16);
static callback_handle_broadcast_t handle_broadcast;
static void set_handle_broadcast(callback_handle_broadcast_t cb, void *userdata) {
handle_broadcast = cb;
data = userdata;
}
%module Test
%include "cpointer.i"
%include "carrays.i"
%include "various.i"
%include "arrays_java.i"
%pointer_functions(int, intp);
%pointer_functions(char, charp);
%include "arrays_java.i"
%include "typemaps.i"
%{
#include <assert.h>
#include "test.h"
struct callback_data {
JNIEnv *env;
jobject obj;
};
void java_callback(int8* arg1, uint16 arg2, void *ptr) {
struct callback_data *data = ptr;
const jclass callbackInterfaceClass = (*data->env)->FindClass(data->env, "BroadcastCallback");
assert(callbackInterfaceClass);
const jmethodID meth = (*data->env)->GetMethodID(data->env, callbackInterfaceClass, "handle", "([C)V");
assert(meth);
jcharArray charArr = (*data->env)->NewCharArray(data->env, arg2);
(*data->env)->CallVoidMethod(data->env, data->obj, meth, (jcharArray)charArr);
}
%}
%typemap(jstype) callback_handle_broadcast_t cb "BroadcastCallback";
%typemap(jtype) callback_handle_broadcast_t cb "BroadcastCallback";
%typemap(jni) callback_handle_broadcast_t cb "jobject";
%typemap(javain) callback_handle_broadcast_t cb "$javainput";
%typemap(in,numinputs=1) (callback_handle_broadcast_t cb, void *userdata) {
struct callback_data *data = malloc(sizeof *data);
data->env = jenv;
data->obj = JCALL1(NewGlobalRef, jenv, $input);
JCALL1(DeleteLocalRef, jenv, $input);
$1 = java_callback;
$2 = data;
}
%include "test.h"
public interface BroadcastCallback {
//public void handle(String broadcast);
public void handle(char[] broadcast);
}
class BtCallback implements BroadcastCallback {
@Override
public void handle(char[] broadcast) {
LOG.debug("Broadcast callback handled: " + broadcast.length);
}
}
BroadcastCallback cb = new BtCallback();
Test.set_handle_broadcast(cb, null);
Test.poll_broadcasts(Test.getHandle_broadcast());