Can shared library call another shared library?

Question

Can one shared library load and call functions from another shared library?

I have Shared library libDsmTestLib.so that use another shared libraries libDsmShared.so and libPINDsmShared.so

LOCAL_PATH := $(call my-dir)

include $(CLEAR_VARS)

LOCAL_MODULE           := DsmTestLib
LOCAL_SRC_FILES        := DSM_Library.cpp

LOCAL_LDLIBS := -lDsmShared
LOCAL_LDLIBS += -lPINDsmShared

include $(BUILD_SHARED_LIBRARY)

when I create libDsmTestLib.so and want to use it in my android java application like this:

package com.dsm;

import android.app.Activity;
import android.os.Bundle;

public class dsmTest extends Activity {
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
    }
      
    static {
        try {
            System.loadLibrary("DsmTestLib");
        }
        catch( UnsatisfiedLinkError e ) {
             System.err.println("Native code library failed to load.\n" + e);
        }
    }  
}

In the catch block I get error

Cannot load library: link_image[1962]: 33 could not load needed library 'libDsmShared.so' for 'libDsmTestLib.so' (load_library[1104]: Library 'libDsmShared.so' not found)

Loadlibrary function cant find library libDsmShared.so that uses my main library libDsmTestLib.so, Who can tell why ? and what can I do to solve this problem ?

Additional Information

I had a static library (.so written in C++) with functionality which I want to use from my Java android application, for that I create .cpp and .h files in which I call the function from the previously created library.

possible duplicate of [NDK - How to use a generated .so library in another project](http://stackoverflow.com/questions/5669220/ndk-how-to-use-a-generated-so-library-in-another-project) — Mark Ingram, Jul 07 '11 at 09:47

score 7 · Answer 1 · answered Sep 14 '11 at 13:03

7

I found solution in this way - explicity loading libraries:

    static {
    try {
        System.loadLibrary("DsmShared");
        System.loadLibrary("DsmTestLib");
    }
    catch( UnsatisfiedLinkError e ) {
         System.err.println("Native code library failed to load.\n" + e);
    }
}

answered Sep 14 '11 at 13:03

Vladimir Berezkin

3,580
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Thank you very much, that solved at leased my problem and is exactly what is written in the first Chapter of the Overview of the NDK-Documentation, but I forgot the first lines I read until I finally got my code to compile in the NDK without errors. (/docs/OVERVIEW.html respectively /documentation.html) – white_gecko Oct 02 '11 at 20:41

score 2 · Answer 2 · edited May 27 '14 at 15:02

2

I had the same error . This is how i solved it and maybe you should try this method.

LOCAL_LDLIBS += -L$(LOCAL_PATH)/libs/libutils.so

edited May 27 '14 at 15:02

Jared Burrows

54,294
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answered Oct 27 '11 at 19:49

Vlad Yarovyi

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It's not -L it should be -l and you should use -lutils and not use the whole path. I'm looking at what people is doing by adding just $(LOCAL_PATH)/libs/libutils.so that for me is like statically linking the lib into your own project/library. – Gonzalo Aguilar Delgado Apr 10 '15 at 11:00

score 1 · Answer 3 · answered Nov 18 '14 at 05:04

1

FYI, I just discovered after a long debugging session that the order in which load lib does matter.

    System.loadLibrary("libDsmShared");
    System.loadLibrary("libPINDsmShared");
    System.loadLibrary("DsmTestLib");

answered Nov 18 '14 at 05:04

Sid Sarasvati

819
9
10

score 1 · Answer 4 · edited Jan 26 '12 at 11:40

1

No, Android VM will search the so file in its own file systems, but not a folder as [C:/cygwin/home/android-ndk-r5b/samples/testingDsm/lib] (I think).

It will search for it from the @androidvm:/system, or other folders specified by java.library.path.

edited Jan 26 '12 at 11:40

Cosmin

21,216
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answered Aug 30 '11 at 08:19

cyoudatu

11
1

score 1 · Answer 5 · edited Nov 23 '11 at 17:24

1

Should be:

LOCAL_LDLIBS += -L$(LOCAL_PATH)/libs/
LOCAL_LDLIBS += -lutils

Also don't forget copying libutils.so into your libs/armeabi folder

edited Nov 23 '11 at 17:24

John Conde

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answered Nov 23 '11 at 17:21

knightwang

11
1

Zennichimaro · Answer 6 · 2012-09-26T02:54:18.013

First, your Activity have to load all the shared libraries

static {
    try {
        System.loadLibrary("libDsmShared");
        System.loadLibrary("libPINDsmShared");
        System.loadLibrary("DsmTestLib");
    }
    catch( UnsatisfiedLinkError e ) {
        System.err.println("Native code library failed to load.\n" + e);
    }
}

Include the "lib*.so" when compiling your native code (in the Android.mk) as in

...
LOCAL_LDLIBS := -L/cygdrive/home/android-ndk-r5b/samples/testingDsm/lib/libDsmShared -lDsmShared
LOCAL_LDLIBS += -L/cygdrive/home/android-ndk-r5b/samples/testingDsm/lib/libPINDsmShared -lPINDsmShared
...

score -3 · Accepted Answer · edited Jun 11 '12 at 22:14

I found this and test it:

The Android dynamic linker had a bug that prevented this from working, but was fixed in 1.6, I believe. If you use the NDK, use "LOCAL_SHARED_LIBRARIES := libB libC" when defining the libA module. This assumes that libB and libC are also NDK modules that were generated with the NDK.

In case libB.so and libC.so are not generated with the NDK, you should do
the following:

in the libA module definition, use LOCAL_LDLIBS += /full/path/to/libB.so /full/path/to/libC.so this ensures that correct symbol exports are generated in libA.so
manually copy libB.so and libC.so to $APP_PROJECT/libs/armeabi before rebuilding your .apk, this ensures that it will be copied to /data/data//lib at installation time by the package manager.

now Android.mk have this look:

LOCAL_PATH := $(call my-dir)

include $(CLEAR_VARS)

LOCAL_MODULE           := DsmTestLib
LOCAL_SRC_FILES        := DSM_Library.cpp


#LOCAL_SHARED_LIBRARIES := DsmShared
#LOCAL_SHARED_LIBRARIES += PINDsmShared


# Set local libs with full path.                                                                
LOCAL_LDLIBS := C:/cygwin/home/android-ndk-r5b/samples/testingDsm/lib/libDsmShared.so           
LOCAL_LDLIBS += C:/cygwin/home/android-ndk-r5b/samples/testingDsm/lib/libPINDsmShared.so        

include $(BUILD_SHARED_LIBRARY)

but now error

Cannot load library: link_image[1962]: 33 could not load needed library 'C:/cygwin/home/android-ndk-r5b/samples/testingDsm/lib/libDsmShared.so' for 'libDsmTestLib.so' (load_library[1104]: Library 'C:/cygwin/home/android-ndk-r5b/samples/testingDsm/lib/libDsmShared.so' not found)

occurred, but when I check C:/cygwin/home/android-ndk-r5b/samples/testingDsm/lib/libDsmShared.so this path I found that the library exists there ... What's the metter ?

Can shared library call another shared library?

Additional Information

7 Answers7

I found this and test it:

now Android.mk have this look:

but now error

Linked