痛飲，轉換C指針，指向浮動[]

Question

我痛飲你怎麼在C轉換返回值的浮動[]在java中

//C Function 
inline float32* b2Body::GetWorldPoint(float32 localX, float32 localY) 
{ 
    b2Vec2 val = b2Mul(m_xf, b2Vec2(localX, localY)); 
    fin[0] = val.x, val.y; 
    fin[1] = val.y; 
    return fin; 
} 

正如你可以看到函數返回FLOAT32 *這是一個兩元素數組。在我痛飲文件I包括

%include cpointer.i 
%include "arrays_java.i" 
%apply float[] {float32*}; 

但我得到的錯誤：

.cpp: In function '_jfloatArray* Java_com_google_fpl_liquidfun_liquidfunJNI_Body_1getWorldPoint_1_1SWIG_11(JNIEnv*, jclass, jlong, jobject, jfloat, jfloat)': 
C:/Users/Garrett/Desktop/liquidfun-master/liquidfun//Box2D/swig/jni/../gen/cpp/armeabi-v7a/liquidfun_wrap.cpp:6147:59: error: 'FillMeInAsSizeCannotBeDeterminedAutomatically' was not declared in this scope 
make.exe: *** [obj/local/armeabi-v7a/objs/liquidfun_jni/gen/cpp/armeabi-v7a/liquidfun_wrap.o] Error 1 

Answer 1

這基本上是相同的解決方案爲an older question on the mailing list：作爲寫這將

%include cpointer.i 
%include "arrays_java.i" 
%typemap(out) float[] 
%{$result = SWIG_JavaArrayOutFloat(jenv, (float *)$1, 2); %} 
%apply float[] {float32*}; 

一個警告導致SWIG假定所有float*作爲返回類型的用法是大小爲2的數組。