[SOLVED] CMake use variables from file

Issue

I'd like to share some variables between my scripts and CMake. It would be nice to re-use bash syntax:

var1=value1
var2=value2
...

I was trying to use the solution from here as the problem is pretty much the same: https://stackoverflow.com/a/17167673/15035275 But the solution didn't work for me.

I created a file config.in containing:

FOO=foobar

And I added this config file to my CMakeLists file:

cmake_minimum_required(VERSION 3.16)

configure_file(
        ${CMAKE_CURRENT_SOURCE_DIR}/config.in
        ${CMAKE_CURRENT_BINARY_DIR}/config
        @ONLY
)

set(CMAKE_VERBOSE_ON)
set(CMAKE_VERBOSE_MAKEFILE ON)


message(STATUS "foo is equal to: ${FOO}")

...

But the variable ${FOO} isn't visible by CMake:

/bin/cmake -DCMAKE_BUILD_TYPE=Debug -G Ninja -S /home/p -B /home/p/cmake-build-debug
-- foo is equal to: 
-- The CXX compiler identification is Clang 10.0.0
...

How can I use the variables from config.in ?

Solution

The answer you linked is not applicable to your problem - I've left a comment on that answer as well.

I don't know of a generic way apart from the regex-based solutions offered by other people in the question you linked.

I can only give you a somewhat more verbose alternative, based on this answer:

execute_process(COMMAND ". config.in && echo -n $FOO" OUTPUT_VARIABLE FOO)
message(STATUS "FOO=${FOO}")

Answered By - Wutz

Answer Checked By - Candace Johnson (WPSolving Volunteer)