问题描述：
安卓ndk-build的时候出现如下错误：
分析问题：
该问题一般由动态库的缺失，或者接口函数未实现所导致。然而该函数在代码中已实现，
Cpp中代码如下：
ErrCode_e Classifier_Init_From_Json( Classifier_t * pClassifier, const char * strRulePath )
{
... ...
}
H头文件中声明如下：
ErrCode_e Classifier_Init_From_Json( Classifier_t * pClassifier, const char * strRulePath );
于是考虑是否未加extern “C”的原因，于是加上如下：
再编译，报错如下：
最终查阅资料：
Thus, the same .h (or .hh or .hpp or what-have-you) could be interpreted as C or C++ at different times,
if different compilation units include them.
If you want the prototypes in the .h file to refer to C symbol names,
then they must have extern "C" when being interpreted as C++,
and they should not have extern "C" when being interpreted as C (as in your case you were getting an error!).
#ifdef __cplusplus
extern "C" { #endif
// Your prototype or Definition #ifdef __cplusplus
} #endif
http://stackoverflow.com/questions/10307762/error-expected-before-string-constant
缺失cpp宏的控制。
解决问题：
