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Failed to connect boost library to my project "Character search error"

I have the following situation:

I created a dynamic library lib.so. This library uses another static library, lib.a. Both of them use the Boost library (I link them in the CMake file). (I use this dynamic library in a Java project)

This is the code for file.cpp in lib.so that calls getFilesFromDirectory () from lib.a

#include "DrawingDetector.h" #include "../../DrawingDetection.h" #include <vector> #include <boost/filesystem/operations.hpp> using namespace std; JNIEXPORT void JNICALL Java_DrawingDetector_detectImage( JNIEnv * env, jobject, jstring jMsg) { const char* msg = env->GetStringUTFChars(jMsg,0); vector<File> filesPic = getFilesFromDirectory(msg,0); env->ReleaseStringUTFChars(jMsg, msg); }

This is the getFilesFromDirectory () code from lib.a:

 #include <string.h> #include <iostream> #include <boost/filesystem/operations.hpp> #include "DrawingDetection.h" using namespace std; using namespace boost; using namespace boost::filesystem; vector<File> getFilesFromDirectory(string dir, int status) { vector<File> files; path directoty = path(dir); directory_iterator end; if (!exists(directoty)) { cout<<"There is no such directory or file!"<<endl; } for (directory_iterator itr(directoty); itr != end; ++itr) { if ( is_regular_file((*itr).path())) { //some code } } return files; }

But when my project calls the lib.so library, it calls the following message:

  java: symbol lookup error: /home/orlova/workspace/kmsearch/Images/branches/DrawingDetection/jni/bin/lib.so: undefined symbol:_ZN5boost11filesystem34path21wchar_t_codecvt_facetEv

As I found out, it crashes in lib.a when it tries to call the boost method of a method. But I declared all forwards headers and linked them in a CMake file. Can you explain why it does not recognize promotion methods?

EDIT

The version of my gcc compiler is 4.6. And if I use 4.5, everything is fine!

Also, if I use some boost methods directly in the .cpp file in lib.so, everything works fine, for example:

  JNIEXPORT void JNICALL Java_DrawingDetector_detectImage( JNIEnv * env, jobject, jstring jMsg) { const char* msg = env->GetStringUTFChars(jMsg,0); path directoty = path("/home/orlova");//if I use boost method here vector<File> filesPic = getFilesFromDirectory(msg,0);// then everything works fine env->ReleaseStringUTFChars(jMsg, msg); }

BUT

 JNIEXPORT void JNICALL Java_DrawingDetector_detectImage( JNIEnv * env, jobject, jstring jMsg) { const char* msg = env->GetStringUTFChars(jMsg,0); //path directoty = path("/home/orlova");//if I don't use boost method here vector<File> filesPic = getFilesFromDirectory(msg,0);// then this method causes before-mentioned error!! env->ReleaseStringUTFChars(jMsg, msg);

}

How can you explain this compiler behavior?

Please note that this error occurs at runtime.

solvable

The problem was the order of the libraries in * target_link_libraries * in the CMake file.

WRONG:

 find_library( LIBRARY_MAIN NAMES lib.a PATHS ../bin ) set ( LIB_JNI jpeg ${OpenCV_LIBS} ${BOOST_LIB} ${LIBRARY_MAIN}//static library is the last in the list of libraries and after boost! ) target_link_libraries( ${PROJECT} ${LIB_JNI} )

RIGHT:

 find_library( LIBRARY_MAIN NAMES lib.a PATHS ../bin ) set ( LIB_JNI ${LIBRARY_MAIN} jpeg ${OpenCV_LIBS} ${BOOST_LIB}//boost library is the last in the list and after static library! ) target_link_libraries( ${PROJECT} ${LIB_JNI} )
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1 answer

It seems that you are dynamically linking Boost.Filesystem - if so, you should make sure that this library is loaded. You can do this by adding it to the LOCAL_LDLIBS line in Android.mk or by pre-loading it manually before loading lib.so into Java code.

Alternatively, just bind Boost (and everything else) statically to lib.so and forget about all this dynamic mess. :)

UPDATE1: Regarding the update you posted - try adding boost_filesystem.a as the last object in the linker line.

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