How debug dynamic library in such situation - c++

Question

Well, I am new to CMake.
I have the following file structure
haze_removal
|---build
|---bin
| |--Test
| |--CMakeLists.txt
|---lib
| |--libtools.so
|---include
| |--tools.hpp
|---test
| |--main.cpp
| |--CMakeLists.txt
|---src
| |--tools.cpp
| |--CMakeLists.txt
|---CMakeLists.txt
The libtools.so is builded from ../src/tools.cpp. I build the whole project in ../build using the following cmake command:
cmake -DCMAKE_BUILD_TYPE=Debug ..
make
The Test is build from ../test/main.cpp
I build this project successfully. But when I debug Test using gdb ./Test, I can't skip in the function that from libtools.so.
These are my CMakeLists.txt from different directories.
CMakeLists.txt under haze_removal/
cmake_minimum_required(VERSION 2.8)
project(haze_removal)
# find needed package
find_package(OpenCV REQUIRED)
# library directory
add_subdirectory(src)
# test
add_subdirectory(test)
CMakeLists.txt under ../src/
# generate dynamic library
# add source file, include directories
aux_source_directory(. TOOLS_SRC)
include_directories(${PROJECT_SOURCE_DIR}/include)
# generate
add_library(tools SHARED ${TOOLS_SRC})
# set output directory and lib's name
set(LIBRARY_OUTPUT_PATH ${PROJECT_SOURCE_DIR}/lib)
set_target_properties(tools PROPERTIES OUTPUT_NAME "tools")
# link library
target_link_libraries(tools ${OpenCV_LIBS})
CMakeLists.txt under ../test/
# add source file, include directories, link directories
aux_source_directory(. EXE_SRC)
include_directories(${PROJECT_SOURCE_DIR}/include)
link_directories(${PROJECT_SOURCE_DIR}/lib)
# generate
add_executable(Test ${EXE_SRC})
# set output directory
set(EXECUTABLE_OUTPUT_PATH ${PROJECT_SOURCE_DIR}/bin)
# link libraries
target_link_libraries(Test ${OpenCV_LIBS} libtools.so)
My question is how I can debug the functions that from libtools.

Answer 1

Well, I find that why I can't step in the dynamic library even though I set CMAKE_BUILD_TYPE=Debug. Because before I set the build model to Debug I used to set CMAKE_BUILD_TYPE=Release. After I change the build model, I didn't delete the files in the build directory.
I don't know whether the above explanation is right or not, but I do solve my problem.
Thx!