Unable to generate a shared library using cmake - c++

Question

I was trying to generate a shared library for my project using cmake, unfortunately I got this error
Undefined symbols for architecture x86_64:
"_SDL_Init", referenced from:
_main in main.cpp.o
"_SDL_Quit", referenced from:
_main in main.cpp.o
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)
If I'm building a static library it works. This is my cmake file :
cmake_minimum_required(VERSION 3.4.1)
project(yanthra_console VERSION 0.1 DESCRIPTION "A 3d Game Engine.")
set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++17 -fexceptions")
set(CMAKE_EXPORT_COMPILE_COMMANDS ON)
set(CMAKE_CONFIGURATION_TYPES "RelWithDebInfo;Release;Debug" CACHE STRING "Build type selections" FORCE)
set(THIRD_PARTY_DIR "../../third-party")
set(MAIN_SOURCE_DIR "../main/src")
set(CMAKE_RUNTIME_OUTPUT_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}/out)
set(CMAKE_LIBRARY_OUTPUT_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}/lib )
set(CMAKE_ARCHIVE_OUTPUT_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}/lib)
include_directories(${THIRD_PARTY_DIR}/SDL/include)
file(GLOB_RECURSE CPP_HEADERS ${MAIN_SOURCE_DIR}/*.hpp)
file(GLOB_RECURSE CPP_SOURCES ${MAIN_SOURCE_DIR}/*.cpp)
add_library(
yanthra
SHARED
${CPP_HEADERS}
${CPP_SOURCES}
)
add_executable(
yanthra_console
${CPP_HEADERS}
${CPP_SOURCES}
)
set_target_properties(
yanthra_console
PROPERTIES
LINK_FLAGS
"-F../Frameworks -framework SDL2 -framework OpenGL"
)
target_link_libraries(yanthra_console PRIVATE yanthra)
I was able to create a static library with executable.Im using Mulit Configuration to build the project.

Answer 1

Looks like a symbol visibility issue.
By default on clang/gcc symbols are hidden.
There is a cppcon talk that talks about this:
https://www.youtube.com/watch?v=m0DwB4OvDXk&list=PL4s9OdsBXD7aXhgqibbEzf8zAM5eiiENs&index=9
Basically either this library doesn't support being built as a shared library.
Or you need to enable that functionality somehow.
Or just force symbol visibility on.