passing C structure to java
Hi all,
Iam new to JNI. I need a small help.
I have structure
typedef struct channel_info
{
int channelno,
char channelname;
char units;
struct channel_info * nextchannel;
}channel_t;
i will fill the structure in c code and i want to pass this structure to java.
and i want to access the data stored in that structure list;
i have gone thorugh examples for passing primitive datatypes. But i did not understand how a structure varaiables can be passed to java.
Thanks in advance.
Always Urs,
Rkanna
[599 byte] By [
rkannaa] at [2007-11-26 21:02:00]
# 1
Like in .NET you should marshal C Structure to Java Class (see Platform Invoke in .NET). But the same algorithm you should implement in JNI code.
Just now I am developing Java Platform Invoke API. This version will run in MS Windows . But in future I will implement the same API for Linux.
The demo is available at
http://www.sharewareplaza.com/Java-Platform-Invoke-API-Demo-version-download_49212.html
# 2
Hi,
Basically you cannot pass a structure from C to Java, you'll have to pass a pointer (the memory address) of the structure to Java then get each primitive type from that memory block.
You can see how it is done with JNative here : http://jnative.free.fr/SPIP-v1-8-3/article.php3?id_article=10
Hope this helps.
Regards,
--Marc (http://jnative.sf.net)
# 3
> Hi all,
> Iam new to JNI. I need a small help.
> I have structure
> typedef struct channel_info
> {
> int channelno,
> char channelname;
> char units;
> struct channel_info * nextchannel;
> channel_t;
>
> i will fill the structure in c code and i want to
> pass this structure to java.
> and i want to access the data stored in that
> structure list;
You have to code each attribute explicitly. So you create a class in java with each attribute (pointer isn't needed.)
In C you then span your C list. Foreach entry you create a new java class instance (via JNI), populate each attribute (via JNI) and than add that java instance to a java list (again via JNI.)
