it seems that i am unable to see the obvious. I wanted to use some Boost library features for my project and know i am getting these nice errors all of a sudden:
Linking CXX executable ATFOR
CMakeFiles/ATFOR.dir/stdafx.cc.o: In function __static_initialization_and_destruction_0(int, int)':
stdafx.cc:(.text+0x3c): undefined reference toboost::system::generic_category()'
stdafx.cc:(.text+0x48): undefined reference to boost::system::generic_category()'
stdafx.cc:(.text+0x54): undefined reference toboost::system::system_category()'
CMakeFiles/ATFOR.dir/Main.cc.o: In function __static_initialization_and_destruction_0(int, int)':
Main.cc:(.text+0x29d): undefined reference toboost::system::generic_category()'
Main.cc:(.text+0x2a9): undefined reference to boost::system::generic_category()'
Main.cc:(.text+0x2b5): undefined reference toboost::system::system_category()'
collect2: error: ld returned 1 exit status
Here you find my CMakeLists.txt, headers, and main: http://pastie.org/8231509
As you can see, i tried a lot playing around with the CMakeLists and i am pretty sure that i have all headers my project requires. Anyways, i've never had such errors before and i really appreciate any suggestions/solutions about what's wrong here since i don't have any ideas left for now. Thx in advance.
You must explicitly add the system library for it to be linked into your program
find_package(Boost REQUIRED COMPONENTS system)
# ^^^^^^ this :)
This must also be done for other Boost libraries that are built separately (regex, thread, etc.) (see here).
The "system" lib is missing in the linking stage. My config is as follows and it fixes the error:
find_package(Boost 1.55.0 REQUIRED COMPONENTS system filesystem)
include_directories(... ${Boost_INCLUDE_DIRS})
link_directories(... ${Boost_LIBRARY_DIRS})
target_link_libraries(... ${Boost_LIBRARIES})
Note that using only
find_package(Boost 1.55.0 REQUIRED)
does not work as ${Boost_LIBRARIES} won't be available then.
Ok, for those interested, the answer of Mark Garcia was a good call but what's more important here is that you need to explicitly link the libs you want from boost like
TARGET_LINK_LIBRARIES(ATFOR ${OpenCV_LIBS} curl ${Boost_SYSTEM_LIBRARY} ${Boost_FILESYSTEM_LIBRARY})
All other options i tried and read about didn't work me, don't know why but i hope this helps someone.
Check if you have the correct build (gcc, msvc...) of your boost libraries. I had this error when I tried linking a project using mingw with libraries built for msvc. If it is different, try building it for the platform you are using in your project.
The first time I used Boost I built it with default parameters resulting in libraries built for msvc, even though I was using mingw for my project.
However CMake did find headers and libraries and everything seemed ok until I started using library features and compiling, that resulted in error mentioned by OP.
Rebuilding boost to toolset=gcc solved it (I was using Windows, CMake + MinGW).
