Solved

Native method problem

Posted on 2000-05-15
4
166 Views
Last Modified: 2010-04-01
Hi

I have a c language method that returns a pointer to struct (defined in c file) and
I want to use this c language to receive the value of the members of the structure
returned by the 'C' function.I cant use pointers in java.So how could I use the c function
to get the values of the struct returned by the 'C' function

Thanks sridhar
0
Comment
Question by:kesavan_sridhar
  • 2
  • 2
4 Comments
 
LVL 3

Expert Comment

by:falter
ID: 2812552
You have to write a wrapper which converts the pointer to an Java Object

The wrapper calls the C-function
- getting the data from the struct
- creating a Java Object
- putting the data into the attributes of the Java object
- return this object to the JVM
0
 

Author Comment

by:kesavan_sridhar
ID: 2815634
To Falter

Helo
Thanks for your response, but is it required to have dependent methods of
a c method to be declared as native method? I mean, if I have a abc() method
of c which I use as a native method
and this abc() method calls some xyz()
method in the c file should I
declare xyz() also as native method
in java file .please explain.


Thanks sridhar
de

0
 
LVL 3

Accepted Solution

by:
falter earned 20 total points
ID: 2816153
No,
you only have to define the native method accessed by Java as a native method in your class.
Methods called inside your JNI code has not to be visible to your Java code.
Think about printf or something else its also a method called and you didn't declare as native Java method.
Also JNI Methods have special Signatures
created by javah from your class.
Like
Java_My_Package_MyClass_nativeMethod

Hope this helps
0
 

Author Comment

by:kesavan_sridhar
ID: 2822078
Thanks very much falter
Bye

sridhar
0

Featured Post

Is Your Active Directory as Secure as You Think?

More than 75% of all records are compromised because of the loss or theft of a privileged credential. Experts have been exploring Active Directory infrastructure to identify key threats and establish best practices for keeping data safe. Attend this month’s webinar to learn more.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

An old method to applying the Singleton pattern in your Java code is to check if a static instance, defined in the same class that needs to be instantiated once and only once, is null and then create a new instance; otherwise, the pre-existing insta…
Introduction This article is the first of three articles that explain why and how the Experts Exchange QA Team does test automation for our web site. This article explains our test automation goals. Then rationale is given for the tools we use to a…
Viewers will learn one way to get user input in Java. Introduce the Scanner object: Declare the variable that stores the user input: An example prompting the user for input: Methods you need to invoke in order to properly get  user input:
This tutorial covers a practical example of lazy loading technique and early loading technique in a Singleton Design Pattern.

943 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question

Need Help in Real-Time?

Connect with top rated Experts

16 Experts available now in Live!

Get 1:1 Help Now