java - How to return double[] in jni input argument -

-

in java code have defined following function signature:

public native boolean getdata( double [] data );

in c++ code i'd populate double array data return java, , returned boolean function indicate whether data set correctly or not.

javah created following c++ function signature:

jniexport jboolean jnicall java_com_test_getdata___3d( jnienv* penv, jclass cls, jdoublearray darray )

how implement function in c++ can return 3 double values generated in c++ code?

i'd similar article: http://www.javaworld.com/article/2077554/learn-java/java-tip-54--returning-data-in-reference-arguments-via-jni.html instead of using stringbuffer, i'd fill in array of doubles values.

it should follows:

jniexport jboolean jnicall java_com_test_getdata___3d( jnienv* penv, jclass cls, jdoublearray darray ) {     jboolean iscopy1;     jdouble* srcarrayelems =             penv->getdoublearrayelements(darray, &iscopy1);     jint n = penv->getarraylength(darray);     jboolean res = false;      // here update srcarrayelems values, maybe set res true      if (iscopy1 == jni_true) {        penv->releasedoublearrayelements(darray, srcarrayelems, jni_abort);     }     return res ; }

when calling getdata array must allocated - means of correct length.

i have not compiled code, can find lots of samples on google, here links:

http://www.ict.nsc.ru/win/docs/java/tutorial/native1.1/implementing/array.html http://statweb.stanford.edu/~naras/java/course/lec5/lec5.html


Comments

Post a Comment

Popular posts from this blog

Java 3D LWJGL collision -

-
i making 3d java game lwjgl library, , wondering how add collision detection, player not go through models. i using obj models. here objloader class, loads models: package renderengine; import java.io.bufferedreader; import java.io.file; import java.io.filenotfoundexception; import java.io.filereader; import java.util.arraylist; import java.util.list; import models.rawmodel; import org.lwjgl.util.vector.vector2f; import org.lwjgl.util.vector.vector3f; public class objloader { public static rawmodel loadobjmodel(string filename, loader loader){ filereader fr = null; try { fr = new filereader(new file("res/"+filename+".obj")); } catch (filenotfoundexception e) { system.err.println("couldn't load file!"); e.printstacktrace(); } bufferedreader reader = new bufferedreader(fr); string line; list<vector3f> vertices = new arraylist<vector3f...
Read more

spring - SubProtocolWebSocketHandler - No handlers -

-
i have ugly error during deploying spring app on jboss. 18:11:16,025 error [org.apache.catalina.core.containerbase.[jboss.web].[default-host].[/consumer]] (msc service thread 1-7) exception sending context initialized event listener instance of class org.springframework.web.context.contextloaderlistener: org.springframework.context.applicationcontextexception: failed start bean 'subprotocolwebsockethandler'; nested exception java.lang.illegalargumentexception: no handlers @ org.springframework.context.support.defaultlifecycleprocessor.dostart(defaultlifecycleprocessor.java:176) [spring-context-4.1.3.release.jar:4.1.3.release] @ org.springframework.context.support.defaultlifecycleprocessor.access$200(defaultlifecycleprocessor.java:51) [spring-context-4.1.3.release.jar:4.1.3.release] @ org.springframework.context.support.defaultlifecycleprocessor$lifecyclegroup.start(defaultlifecycleprocessor.java:346) [spring-context-4.1.3.release.jar:4.1.3.release] @ org.s...
Read more

methods - python can't use function in submodule -

-
my folder structure this: pythonstuff/ program.py modulea/ __init__.py foo.py bar.py here's code bar.py : def hello(): print("hello, world!") here's code program.py : #!/usr/bin/env python3 modulea import bar bar.hello() i run $ python3 program.py somehow error: file "program.py", line 3, in <module> bar.hello() attributeerror: 'module' object has no attribute 'hello' edit: __init__.py file empty. edit2: after trying realized had bar.py in root directory contained hello() method. bar.py in modulea/ directory empty. add it import os __all__ = [] module in os.listdir(os.path.dirname(__file__)): if module != '__init__.py' , module[-3:] == '.py': __all__.append(module[:-3]) the init .py files required make python treat directories containing packages; done prevent directories common name, such string, unintentionally hiding v...
Read more