JNI共享库中的未定义符号，可执行文件正在运行

Question

I am really unexperienced when it comes to C++ so I hope this just a small mistake that causes this error. Sorry that the post is so long but I tried to include all the important details.

So here is what I am trying to do: I am using an external library that comes in the form of two folders with a makefile each. I am trying to create a JNI library with one additional cpp file and the JNI header in an .h file.

So the folder structure is like this: -> libcds/src with a makefile that creates libcds.a
-> SSA2 with a makefile that creates SSA.a
-> myFolder with my cpp and h file and a makefile that should create the library

So here are the different makefiles:

libcds/src:

CPP=g++

CPPFLAGS=-O9 -w -DNDEBUG 

INCL=-I../includes/

CODERS_DIR=coders
CODERS_OBJECTS=$(CODERS_DIR)/huff.o $(CODERS_DIR)/huffman_codes.o

STATIC_PERMUTATION_DIR=static_permutation
STATIC_PERMUTATION_OBJECTS=$(STATIC_PERMUTATION_DIR)/perm.o ...

STATIC_BITSEQUENCE_DIR=static_bitsequence
STATIC_BITSEQUENCE_OBJECTS=$(STATIC_BITSEQUENCE_DIR)/static_bitsequence.o ..

STATIC_SEQUENCE_DIR=static_sequence
STATIC_SEQUENCE_OBJECTS=$(STATIC_SEQUENCE_DIR)/static_sequence.o, ..., wt_coder.o

UTILS_DIR=utils
UTILS_OBJECTS=$(UTILS_DIR)/alphabet_mapper_none.o $(UTILS_DIR)/alphabet_mapper.o

%.o: %.cpp

$(CPP) $(CPPFLAGS) $(INCL) -c $< -o $@

all: lib 

lib: pre $(CODERS_OBJECTS) $(STATIC_BITSEQUENCE_OBJECTS) $(STATIC_SEQUENCE_OBJECTS) $(UTILS_OBJECTS) $(STATIC_PERMUTATION_OBJECTS)
    ar rcs ../lib/libcds.a $(CODERS_OBJECTS) $(STATIC_BITSEQUENCE_OBJECTS) $(STATIC_SEQUENCE_OBJECTS) $(UTILS_OBJECTS) $(STATIC_PERMUTATION_OBJECTS)

pre:
    cp basics.h ../includes/
    cp */*.h ../includes/

SSA2:

CC=g++

CFLAGS=-w -O9 -DNDEBUG -I../libcds/includes/
CODERS_DIR=../libcds/src/coders

CODERS_OBJECTS=$(CODERS_DIR)/huff.o $(CODERS_DIR)/huffman_codes.o

STATIC_BITSEQUENCE_DIR=../libcds/src/static_bitsequence

STATIC_BITSEQUENCE_OBJECTS=$(STATIC_BITSEQUENCE_DIR)/static_bitsequence.o ...

STATIC_SEQUENCE_DIR=../libcds/src/static_sequence

STATIC_SEQUENCE_OBJECTS=$(STATIC_SEQUENCE_DIR)/static_sequence.o ...

UTILS_DIR=../libcds/src/utils

UTILS_OBJECTS=$(UTILS_DIR)/alphabet_mapper_none.o $(UTILS_DIR)/alphabet_mapper.o

all: index

# pattern rule for all objects files

%.o: %.c *.h

    $(CC) -c $(CFLAGS) $< -o $@

%.o: %.cpp *.h

    $(CC) -c $(CFLAGS) $< -o $@

index: bitrankw32int.o bitarray.o  ds/ds.o ds/globals.o ds/helped.o ds/shallow.o ds/deep2.o ds/blind2.o SSA.o

    cp ../libcds/lib/libcds.a SSA.a

    ar rcs SSA.a SSA.o bitrankw32int.o bitarray.o ds/ds.o ds/globals.o ds/shallow.o ds/helped.o ds/deep2.o ds/blind2.o

My makefile:

CC=g++ -I $(JAVA_HOME)/include -I $(JAVA_HOME)/include/linux
LD_LIBRARY_PATH=./
JNI_NAME= indexlib

all: test

%.o: %.c *.h
    $(CC) -c $(CFLAGS) $< -o $@

test_index: 
    $(CC) run_queries.c -o testIndex SSA.a

test_index_lib: run_queries.o
    ld -shared -soname lib$(JNI_NAME).so -o lib$(JNI_NAME).so run_queries.o SSA.a -lc

The executable testIndex works without issues. The resulting library, however can't be loaded by Java with the error message:

undefined symbol: _ZNSt8ios_base4InitC1Ev

When I use nm to find that symbol I get the following result:

000131b0 W _ZN8wt_coderD2Ev
U _ZNKSt5ctypeIcE13_M_widen_initEv
U _ZNSo3putEc
U _ZNSo5flushEv
U _ZNSo9_M_insertImEERSoT_
U _ZNSt8ios_base4InitC1Ev
U _ZNSt8ios_base4InitD1Ev
U _ZSt16__ostream_insertIcSt11char_traitsIcEERSt13basic_ostreamIT_T0_ES6_PKS3_i
U _ZSt16__throw_bad_castv
U _ZSt4cout

And with --demangle it looks like this: 000131b0 W wt_coder::~wt_coder()
U std::ctype::_M_widen_init() const
U std::ostream::put(char)
U std::ostream::flush()
U std::ostream& std::ostream::_M_insert(unsigned long)
U std::ios_base::Init::Init()
U std::ios_base::Init::~Init()
U std::basic_ostream >& std::__ostream_insert

(std::basic_ostream >&, char const*, int) U std::__throw_bad_cast()
U std::cout

So actually this could be related to Linker error: undefined reference to `std::ctype<char>::_M_widen_init()

Answer 1

I think you are not linking to the C++ standard library. You need it because one of the libraries you are linking to is C++.

In the first case (target test_index) everything works okay because you are using g++ to compile and link, and it will link to libstdc++ implicitly. In the shared library case you are linking with ld which does not link libstdc++ implicitly.

You can use g++ to compile and link the shared library or add libstdc++ explicitly with -lstdc++ . Either should work.

Answer 2

因此问题最终变得非常简单：我必须使用g ++来创建库，而不是ld