Android(安卓)NDK学习（7）NDK测试时遇到的问题：C与C++互相调用

贴代码：

test.h

int adds(int a,int b);int subs(int a,int b);

test.c

#include "test.h"int adds(int a,int b){   return (a-b);}int subs(int a,int b){   return (a+b);}

com_ycan_ycantestlib.h

/* DO NOT EDIT THIS FILE - it is machine generated */#include <jni.h>/* Header for class com_ycan_ycantestlib */#ifndef _Included_com_ycan_ycantestlib#define _Included_com_ycan_ycantestlib#ifdef __cplusplusextern "C" {#endif/* * Class:     com_ycan_ycantestlib * Method:    add * Signature: (II)I */JNIEXPORT jint JNICALL Java_com_ycan_ycantestlib_add  (JNIEnv *, jobject, jint, jint);/* * Class:     com_ycan_ycantestlib * Method:    sub * Signature: (II)I */JNIEXPORT jint JNICALL Java_com_ycan_ycantestlib_sub  (JNIEnv *, jobject, jint, jint);#ifdef __cplusplus}#endif#endif

com_ycan_ycantestlib.cpp

include "com_ycan_ycantestlib.h"#ifdef __cplusplusextern "C" {#endif#include "test.h"#ifdef __cplusplus}#endifJNIEXPORT jint JNICALL Java_com_ycan_ycantestlib_add  (JNIEnv *evn, jobject thiz, jint a, jint b){    int c  =adds(a,b);    return c;}JNIEXPORT jint JNICALL Java_com_ycan_ycantestlib_sub  (JNIEnv *evn, jobject thiz, jint a, jint b){    int c  =subs(a,b);    return c;}

Android.mk

#Android.mk和需要编译的源文件在同一目录下#LOCAL_PATH:= $(call my-dir)#源文件列表#common_SRC_FILES  :=\ test.c \ com_ycan_ycantestlib.cpp#头文件列表#common_C_INCLUDES :=\ test.h \ com_ycan_ycantestlib.h#模块开始#include $(CLEAR_VARS)#源文件列表#LOCAL_SRC_FILES := $(common_SRC_FILES) #头文件列表#LOCAL_C_INCLUDES += $(common_C_INCLUDES)#生成的程序名#LOCAL_MODULE:= com_ycan_ycantestlib  #此处有三个选择：可执行程序，动态库，静态库#include $(BUILD_SHARED_LIBRARY)

这是c++调用c的情况，解决问题的关键就是com_ycan_ycantestlib.cpp中的这段：

#ifdef __cplusplus   extern "C" {  #endif   #include "test.h"   #ifdef __cplusplus   }  #endif

反过来，也是一样的，需要注意的是这段只能加在c++代码中。

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