How to debug error “Symbol lookup error: undefined symbol”

问题

I created an app (api_tests) that uses a library (libstorage.so) that linked to oracle occi library (libocci.so.12.1) and compiled it. When I run this app, I get an error:

api_tests
api_tests: symbol lookup error: ./libstorage.so: undefined symbol: _ZN6oracle4occi11Environment17createEnvironmentENS1_4ModeEPvPFS3_S3_mEPFS3_S3_S3_mEPFvS3_S3_E

However this library with this symbol exists in the current directory:

ls | grep libocci
libocci.so*
libocci.so.11.1*
libocci.so.12.1*

nm libocci.so.12.1 | grep _ZN6oracle4occi11Environment17createEnvironmentENS1_4ModeEPvPFS3_S3_mEPFS3_S3_S3_mEPFvS3_S3_E
0000000000097e70 T _ZN6oracle4occi11Environment17createEnvironmentENS1_4ModeEPvPFS3_S3_mEPFS3_S3_S3_mEPFvS3_S3_E
0000000000125014 r _ZN6oracle4occi11Environment17createEnvironmentENS1_4ModeEPvPFS3_S3_mEPFS3_S3_S3_mEPFvS3_S3_E$$LSDA

The current path is added to LD_LABRARY_PATH:

echo $LD_LIBRARY_PATH
./:/usr/vacpp/bin/../lib:/lib

I'm wondering what can be wrong with my library and how I can debug the issue?

Update: It looks like this library was not linked (at least ldd doesn't show this dependency). I guess it was mistake in makefile and it was compiled but failes in runtime.

回答1:

nm libocci.so.12.1

There are two problems with above command:

You don't know whether libocci.so.12.1 is actually getting loaded into your process. To answer the "which libocci is getting loaded", run with LD_DEBUG=libs.
Just because the symbol is present in the symbol table of libocci.so.12.1 doesn't mean that it's available for dynamic linking. It must be available in the dynamic symbol table, which you can examine with nm -D libocci.so.12.1

来源：https://stackoverflow.com/questions/38799192/how-to-debug-error-symbol-lookup-error-undefined-symbol

标签

c++

linker

shared-libraries