DA-- DA-- - 4 months ago 61
C++ Question

CMake: Linking statically against libgcc and libstdc++ into a shared library

Problem:

I have problems linking glibcc/glibc++ into a shared library using CMake and GCC4.9 on my Ubuntu 16.04 installation.

Additional conditions:

Loading the shared library gives a problem om the Red Hat production environment(where I copy it to), I believe because it uses a different libstc++ version(error: GLIBCXX_3_4_20 not found). I do not have sudo rights and cannot upgrade the machine.

As I derived from this blog, this post, I tried linking static linking against libgcc and libgc++ using:

set(CMAKE_EXE_LINKER_FLAGS "-static-libgcc -static-libstdc++ -static")


and againg using

set(CMAKE_SHARED_LINKER_FLAGS "-static-libgcc -static-libstdc++ -static")


But that doesn't work. What does work is this CMake script:

add_library(myLib SHARED ${SOURCE_FILES})
set(CMAKE_EXE_LINKER_FLAGS " -static")
target_link_libraries(myLib -static-libgcc -static-libstdc++)


This must be the wrong way of doing this, to my knowledge -static-libgcc and -static-libstdc++ are linker options and not libraries...

Question:
How do I link statically against -libgcc and -libstdc++ correctly?

Thanks in advance!

Answer

Yes, target_link_libraries is a correct way to set linker flags or linker options.

Documentation of target_link_libraries:

Specify libraries or flags to use when linking a given target.

Item names starting with -, but not -l or -framework, are treated as linker flags.

https://cmake.org/cmake/help/v3.0/command/target_link_libraries.html (emphasis not in original)