Question

I’m trying to compile the following c++ code that implements Context Tree Switching (More info on the download page):

Zip archive, 0.2 MB

which requires some boost libraries. I download the latest version from boost.org and built all libraries that needed building following the instructions on the website. I also modified the makefile included in the archive to add the boost lib path and boost_system, but I still get an error. Here’s the makefile i’m using:

PROGRAM = cts
SOURCES = $(wildcard *.cpp)
OBJECTS = $(SOURCES:.cpp=.o)
CFLAGS = -Wall
LDFLAGS = -lboost_program_options -lboost_filesystem -lboost_system

$(PROGRAM): $(OBJECTS) Makefile
    g++ $(CFLAGS) -L/home/users/mnembrini/opt/boost/lib $(LDFLAGS) -o $(PROGRAM) $(OBJECTS)

# Include known dependecies from -MMD
#-include $(OBJECTS:.o=.d)

%.o: %.cpp
    g++ -MMD $(CFLAGS) -I/home/users/mnembrini/opt/boost/include -c $<

clean:
    rm -f $(OBJECTS) *.d

.PHONY: clean

where boost is in ~/opt/boost (constains lib and include subdir). And here’s the linking error:

mnembrini@meem:~/src/cts-v1 $ make
g++ -MMD -Wall -I/home/users/mnembrini/opt/boost/include -c ac.cpp
g++ -MMD -Wall -I/home/users/mnembrini/opt/boost/include -c cts.cpp
cts.cpp: In member function ‘virtual void SwitchingTree::update(bit_t)’:
cts.cpp:402:12: warning: variable ‘snc’ set but not used [-Wunused-but-set-variable]
cts.cpp: In member function ‘virtual double SwitchingTree::prob(bit_t)’:
cts.cpp:432:12: warning: variable ‘snc’ set but not used [-Wunused-but-set-variable]
g++ -MMD -Wall -I/home/users/mnembrini/opt/boost/include -c ctw.cpp
g++ -MMD -Wall -I/home/users/mnembrini/opt/boost/include -c icsilog.cpp
g++ -MMD -Wall -I/home/users/mnembrini/opt/boost/include -c main.cpp
g++ -MMD -Wall -I/home/users/mnembrini/opt/boost/include -c PowFast.cpp
g++ -Wall -L/home/users/mnembrini/opt/boost/lib -lboost_program_options -lboost_filesystem -lboost_system -o cts ac.o cts.o ctw.o icsilog.o main.o PowFast.o
cts.o: In function `__static_initialization_and_destruction_0(int, int)':
cts.cpp:(.text+0x1743): undefined reference to `boost::system::generic_category()'
cts.cpp:(.text+0x174f): undefined reference to `boost::system::generic_category()'
cts.cpp:(.text+0x175b): undefined reference to `boost::system::system_category()'
ctw.o: In function `__static_initialization_and_destruction_0(int, int)':
ctw.cpp:(.text+0xfcf): undefined reference to `boost::system::generic_category()'
ctw.cpp:(.text+0xfdb): undefined reference to `boost::system::generic_category()'
ctw.cpp:(.text+0xfe7): undefined reference to `boost::system::system_category()'
main.o: In function `showHelp()':
main.cpp:(.text+0x1c): undefined reference to `boost::program_options::operator<<(std::basic_ostream<char, std::char_traits<char> >&, boost::program_options::options_description const&)'
main.o: In function `initOptions(int, char**, boost::program_options::variables_map&)':
main.cpp:(.text+0x10f): undefined reference to `boost::program_options::options_description::add_options()'
main.cpp:(.text+0x129): undefined reference to `boost::program_options::options_description_easy_init::operator()(char const*, char const*)'
main.cpp:(.text+0x13e): undefined reference to `boost::program_options::options_description_easy_init::operator()(char const*, boost::program_options::value_semantic const*, char const*)'
main.cpp:(.text+0x153): undefined reference to `boost::program_options::options_description_easy_init::operator()(char const*, boost::program_options::value_semantic const*, char const*)'
main.cpp:(.text+0x166): undefined reference to `boost::program_options::options_description_easy_init::operator()(char const*, boost::program_options::value_semantic const*, char const*)'
main.cpp:(.text+0x1d6): undefined reference to `boost::program_options::store(boost::program_options::basic_parsed_options<char> const&, boost::program_options::variables_map&, bool)'
main.cpp:(.text+0x200): undefined reference to `boost::program_options::notify(boost::program_options::variables_map&)'
main.o: In function `__static_initialization_and_destruction_0(int, int)':
main.cpp:(.text+0x1f13): undefined reference to `boost::system::generic_category()'
main.cpp:(.text+0x1f1f): undefined reference to `boost::system::generic_category()'
[snip (2-3 screens like above)]
collect2: ld returned 1 exit status
make: *** [cts] Error 1

I’m using Gcc 4.6.3 on Ubuntu 12.04 64bit.

Answer 1

Place all the libraries after all the object files within the command line. The order is important here, unlike on some other operating systems.