How to retrieve a user environment variable in CMake Windows

Question

I know how to retrieve a normal machine wide environment variable in CMAKE using   ENV EnvironmentVariableName    but I can not retrieve a user specific environment variable  Is it possible and how

User · Answer

You can also invoke cmake itself to do this in a cross-platform way:

cmake -E env EnvironmentVariableName="Hello World" cmake ..

env [--unset=NAME]... [NAME=VALUE]... COMMAND [ARG]...

Run command in a modified environment.

Just be aware that this may only work the first time. If CMake re-configures with one of the consecutive builds (you just call e.g. make, one CMakeLists.txt was changed and CMake runs through the generation process again), the user defined environment variable may not be there anymore (in comparison to system wide environment variables).

So I transfer those user defined environment variables in my projects into a CMake cached variable:

cmake_minimum_required(VERSION 2.6)

project(PrintEnv NONE)

if (NOT "$ENV{EnvironmentVariableName}" STREQUAL "")
    set(EnvironmentVariableName "$ENV{EnvironmentVariableName}" CACHE INTERNAL "Copied from environment variable")
endif()

message("EnvironmentVariableName = ${EnvironmentVariableName}")

Reference

CMake - Command Line Tool Mode

User · Answer

Environment variables  that you modify using the System Properties  are only propagated to subshells when you create a new subshell   If you had a command line prompt  DOS or cygwin  open when you changed the User env vars  then they won t show up   You need to open a new command line prompt after you change the user settings   The equivalent in Unix Linux is adding a line to your  bash rc  you need to start a new shell to get the values

User · Answer

You need to have your variables exported  So for example in Linux   export EnvironmentVariableName foo   Unexported variables are empty in CMAKE

User · Answer

Getting variables into your CMake script  You can pass a variable on the line with the cmake invocation   FOO 1 cmake   or by exporting a variable in BASH   export FOO 1   Then you can pick it up in a cmake script using    ENV FOO

[windows] How to retrieve a user environment variable in CMake (Windows)

Examples related to windows

Examples related to environment-variables

Examples related to cmake