CMakeLists.txt suggestion

[Michael Lewis]

Hi,

If a minimal CMakeLists.txt file is added to the project, e.g.

project(mpc C)
set(CMAKE_C_STANDARD 99)
add_library(mpc mpc.c mpc.h)

Then this would allow convenient import of mpc into other projects that used CMake, for example:

cmake_minimum_required(VERSION 3.19)
project(scratchpad3)
set(CMAKE_CXX_STANDARD 17)

include(FetchContent)

FetchContent_Declare(
        mpc
        GIT_REPOSITORY https://github.com/lewismj/mpc.git
        GIT_TAG master
)

FetchContent_GetProperties(mpc)
if(NOT mpc_POPULATED)
    FetchContent_Populate(mpc)
    add_subdirectory(${mpc_SOURCE_DIR} ${mpc_BINARY_DIR})
endif()

include_directories(${CMAKE_BINARY_DIR}/_deps/mpc-src)

add_executable(scratchpad3 main.cpp)
target_link_libraries(${PROJECT_NAME}  mpc)

I cloned and tested this, it allows downstream users of cmake to just use 'FetchContent' which is quite nice, if you want to allow someone to build from scratch without having dependencies installed?

[Sam Stuewe]

Sorry, I errantly closed that. Pardon the noise.

[Sam Stuewe]

So, I have two questions (not being hugely familiar with CMake):

1. I don't think this compiles mpc with all the options that the Makefile specifies right now; is it much more complex to offer this?
2. I think if mpc supported multiple build systems, it's essentially guaranteed that they'll get out-of-sync. Is it possible to generate the CMakeLists.txt from the Makefile (e.g., via a shell script or a make target) so they can remain in-sync?

(worth noting that I'm not the maintainer of this project, but I have worked on projects that support multiple build-systems.)

[Michael Lewis]

CMake is a generic cross platform build tool. It isn't a replacement for make; CMake would generate the build files, e.g. make files. It is a more convenient way to define the build.

So, cmake; make; make install is usual build process.
e.g. https://cmake.org/cmake/help/latest/guide/tutorial/index.html

Example, MSFT, cpp rest sdk: https://github.com/microsoft/cpprestsdk
Apple, Foundation DB, https://github.com/apple/foundationdb

It is pretty much a standard in the C/C++ world.

[Daniel Holden]

Generally I'm not a big fan of cmake, and given the CMakeLists.txt you propose is only three lines I'm sure the people who do want to use it can add it themselves. The recommended way to use this project is just to copy the source files directly. Having the Makefile in the repo is useful for various things e.g. running tests and while it is there we may as well configure it so it can build and install the lib statically or dynamically too.

[Sam Stuewe]

@lewismj, I'm familiar enough with cmake to know what it is and how it normally works. I thought you were suggesting adding that CMakeLists.txt in addition to the Makefile that's already integrated rather than replacing it with cmake. I personally don't love cmake; I find it a huge additional dependency without a ton of benefit (until it gets to huge projects).

[Michael Lewis]

Ok, CMake is usually used for defining the stuff like running tests and installation etc... But I think I'll just add it locally thanks. I would recommend learning about its capabilities though.