UnsatisfiedLinkError while loading library using System.loadLibrary

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ratheesh.pai@gmail.com - 24 Nov 2006 05:35 GMT

I am facing a issue while trying to load a library using
System.loadLibrary

Sample Code:

public static void main(String[] args) {
System.loadLibrary("xxx")

}

Throws the Exception:

libxxx.so: undefined symbol: yyyyy

The libxxx.so file is present in $LD_LIBRARY_PATH
Platform: Red-Hat Linux
JAVA version: 1.5

The file yyyyy.o is contained in some other archive files. I do not
want to include this .o in this library libxxx.so. How to tell JVM
about the location of this .o (inside a .a file) while it loads the
libxxx.so library

Has anyone ever faced a similar problem, or has any clues regarding
this problem as to how to fix this

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Gordon Beaton - 24 Nov 2006 06:03 GMT

> libxxx.so: undefined symbol: yyyyy
>
> The libxxx.so file is present in $LD_LIBRARY_PATH
> Platform: Red-Hat Linux
> JAVA version: 1.5

System.loadLibrary() didn't fail. It was your attempt to invoke the
non-existing function that caused the exception.

If the missing symbol is in libyyy.so then your libxxx.so is dependent
on libyyy.so, and you need to specify that when you link libxxx.so,
i.e.:

gcc -shared -f libyyy.so x.o -o libxxx.so

Also, libyyy.so must be in LD_LIBRARY_PATH at runtime.

Use "readelf -d libxxx.so" to check that there is NEEDS entry
mentioning libyyy.so. Use "ldd -v libxxx.so" to confirm that it can be
resolved at runtime.

/gordon

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[ don't email me support questions or followups ]
g o r d o n + n e w s @ b a l d e r 1 3 . s e

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Nigel Wade - 24 Nov 2006 10:52 GMT

> I am facing a issue while trying to load a library using
> System.loadLibrary
[quoted text clipped - 21 lines]
> Has anyone ever faced a similar problem, or has any clues regarding
> this problem as to how to fix this

Your criteria are mutually exclusive. You either link libxxx.so against the
other archive (and include the object in libxxx.so) or you are doomed to
failure.

There is no way to make an executable retrieve an object from an archive file.
The object must be included in the executable, or one of the DSOs it loads.
Since there is no way to modify the java executable to include the object in
that, your only choice is to include it in your DSO.

Signature

Nigel Wade, System Administrator, Space Plasma Physics Group,
University of Leicester, Leicester, LE1 7RH, UK
E-mail : nmw@ion.le.ac.uk
Phone : +44 (0)116 2523548, Fax : +44 (0)116 2523555

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UnsatisfiedLinkError while loading library using System.loadLibrary

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