Variables

Filename: CMakeLists.txt

cmake_minimum_required(VERSION 3.31)

project(variables LANGUAGES C)

message("CMAKE_SOURCE_DIR=${CMAKE_SOURCE_DIR}") # "/workspace" or similar
message("CMAKE_BINARY_DIR=${CMAKE_BINARY_DIR}") # "/workspace/build" or similar
message("CMAKE_C_COMPILER=${CMAKE_C_COMPILER}") # "/usr/bin/cc" or similar
message("CMAKE_CXX_COMPILER=${CMAKE_CXX_COMPILER}") # "/usr/bin/c++" or similar
message("CMAKE_AR=${CMAKE_AR}") # "/usr/bin/ar" or similar
message("CMAKE_RANLIB=${CMAKE_RANLIB}") # "/usr/bin/ranlib" or similar
message("PROJECT_NAME=${PROJECT_NAME}") # "variables"
message("CMAKE_HOST_UNIX=${CMAKE_HOST_UNIX}") # TRUE if the host system is UNIX-like
message("CMAKE_WIN32=${CMAKE_WIN32}") # TRUE if the target system is Windows

set(MY_BOOL ON) # BOOL type
set(MY_EXE_NAME "variables") # STRING type
set(MY_SOURCE_FILES "./src/main.c" "./src/stats.c") # list type

add_executable("${MY_EXE_NAME}" ${MY_SOURCE_FILES})

Filename: src/main.c

#include <stdio.h>
#include "./stats.h"

int main() {
    printf("Hello, %s!\n", "World");
    printf("The average of 1, 2, and 3 is %f.\n", average_of_three(1, 2, 3));
    return 0;
}

Filename: src/stats.c

#include "./stats.h"

double average_of_three(double a, double b, double c) {
    return (a + b + c) / 3;
}

Filename: src/stats.h

#pragma once

double average_of_three(double a, double b, double c);

$ cmake -B ./build/
-- The C compiler identification is GNU 9.4.0
-- The CXX compiler identification is GNU 9.4.0
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - done
-- Check for working C compiler: /usr/bin/cc - skipped
-- Detecting C compile features
-- Detecting C compile features - done
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Check for working CXX compiler: /usr/bin/c++ - skipped
-- Detecting CXX compile features
-- Detecting CXX compile features - done
CMAKE_SOURCE_DIR=/workspaces/cmakebyexample.jcbhmr.com/listings/03-variables
CMAKE_BINARY_DIR=/workspaces/cmakebyexample.jcbhmr.com/listings/03-variables/build
CMAKE_C_COMPILER=/usr/bin/cc
CMAKE_CXX_COMPILER=/usr/bin/c++
CMAKE_AR=/usr/bin/ar
CMAKE_RANLIB=/usr/bin/ranlib
PROJECT_NAME=variables
CMAKE_HOST_UNIX=1
CMAKE_WIN32=
-- Configuring done (0.4s)
-- Generating done (0.0s)
-- Build files have been written to: /workspaces/cmakebyexample.jcbhmr.com/listings/03-variables/build
$ cmake --build ./build/
[ 33%] Building C object CMakeFiles/variables.dir/src/main.c.o
[ 66%] Building C object CMakeFiles/variables.dir/src/stats.c.o
[100%] Linking C executable variables
[100%] Built target variables
$ ./build/variables 
Hello, World!
The average of 1, 2, and 3 is 2.000000.

CMake by Example

Variables