I work on the native part of my C# lib written in C. This part provides native socket API for main platforms win/mac/linux. I'm already building sources independently on each platform using CMake.
My current goal builds lib for these platforms at my dev machine (MacOS).
Platforms list:
# 64 bit builds
- linux64
- osx
- win64
# 32 bit builds
- linux32
- win32
After reading CMake docs about cross-compiling, and search some examples on GitHub I still have trouble with this task.
Docs: https://cmake.org/cmake/help/latest/manual/cmake-toolchains.7.html
GitHub search: https://github.com/search?q=CMake+cross+compiling&type=Repositories
Could anyone explain a detailed step-by-step algorithm of what could I do to reach this goal? A Simple "Hello World!" example with shared lib would be very helpful or link on the existing sample/project.
Thanks.
Update:
Project structure:
build/
cmake/
x64-linux.cmake
x86_64-osx.cmake
src/
native_socket.c
native_socket.h
CMakeLists.txt
build_native.sh
CMakeLists.txt:
cmake_minimum_required(VERSION 3.20.1)
project(native_socket LANGUAGES C)
add_library(native_socket SHARED src/native_socket.c)
set_target_properties(native_socket PROPERTIES PREFIX "")
build_native.sh:
cmake -H. -B build/linux64 -DCMAKE_BUILD_TYPE=Release -DCMAKE_TOOLCHAIN_FILE=cmake/x64-linux.cmake
cmake --build ./build/linux64 -v
cmake -H. -B build/osx -DCMAKE_BUILD_TYPE=Release -DCMAKE_TOOLCHAIN_FILE=cmake/x86_64-osx.cmake
cmake --build ./build/osx
x86_64-osx.cmake:
set(CMAKE_SYSTEM_NAME Darwin)
set(CMAKE_C_COMPILER gcc)
x64-linux.cmake:
set(CMAKE_SYSTEM_NAME Linux)
set(CMAKE_SYSTEM_VERSION 1)
set(CMAKE_C_COMPILER gcc)
set(CMAKE_CROSSCOMPILING TRUE)
set(CMAKE_FIND_ROOT_PATH_MODE_PROGRAM NEVER)
set(CMAKE_FIND_ROOT_PATH_MODE_LIBRARY ONLY)
set(CMAKE_FIND_ROOT_PATH_MODE_INCLUDE ONLY)
After running build script, I see a linker error in the terminal:
% ./build_native.sh
-- Configuring done
-- Generating done
-- Build files have been written to: /Users/rdcm/dev/projects/PInvoke/PInvoke/build/linux64
/Applications/CMake.app/Contents/bin/cmake -S/Users/rdcm/dev/projects/PInvoke/PInvoke -B/Users/rdcm/dev/projects/PInvoke/PInvoke/build/linux64 --check-build-system CMakeFiles/Makefile.cmake 0
/Applications/CMake.app/Contents/bin/cmake -E cmake_progress_start /Users/rdcm/dev/projects/PInvoke/PInvoke/build/linux64/CMakeFiles /Users/rdcm/dev/projects/PInvoke/PInvoke/build/linux64//CMakeFiles/progress.marks
/Applications/Xcode.app/Contents/Developer/usr/bin/make -f CMakeFiles/Makefile2 all
/Applications/Xcode.app/Contents/Developer/usr/bin/make -f CMakeFiles/native_socket.dir/build.make CMakeFiles/native_socket.dir/depend
cd /Users/rdcm/dev/projects/PInvoke/PInvoke/build/linux64 && /Applications/CMake.app/Contents/bin/cmake -E cmake_depends "Unix Makefiles" /Users/rdcm/dev/projects/PInvoke/PInvoke /Users/rdcm/dev/projects/PInvoke/PInvoke /Users/rdcm/dev/projects/PInvoke/PInvoke/build/linux64 /Users/rdcm/dev/projects/PInvoke/PInvoke/build/linux64 /Users/rdcm/dev/projects/PInvoke/PInvoke/build/linux64/CMakeFiles/native_socket.dir/DependInfo.cmake --color=
Dependencies file "CMakeFiles/native_socket.dir/src/native_socket.c.o.d" is newer than depends file "/Users/rdcm/dev/projects/PInvoke/PInvoke/build/linux64/CMakeFiles/native_socket.dir/compiler_depend.internal".
Consolidate compiler generated dependencies of target native_socket
/Applications/Xcode.app/Contents/Developer/usr/bin/make -f CMakeFiles/native_socket.dir/build.make CMakeFiles/native_socket.dir/build
[ 50%] Linking C shared library native_socket.so
/Applications/CMake.app/Contents/bin/cmake -E cmake_link_script CMakeFiles/native_socket.dir/link.txt --verbose=1
/usr/bin/gcc -fPIC -O3 -DNDEBUG -shared -Wl,-soname,native_socket.so -o native_socket.so CMakeFiles/native_socket.dir/src/native_socket.c.o
ld: unknown option: -soname
clang: error: linker command failed with exit code 1 (use -v to see invocation)
make[2]: *** [native_socket.so] Error 1
make[1]: *** [CMakeFiles/native_socket.dir/all] Error 2
make: *** [all] Error 2
Questions:
- Should I additional install dev tools on my dev machine for building .so/.dll lib for Linux/Win?
- How should I change CMake config files for the successful build?
- A real simple example that works will be very helpful. I think no matter in which environment Linux/MacOS because I have plans to automate this process.
