linuxcmakeenvironment-variablescross-compilingbuild-system

cmake : Set environment variables from a script


I have a script that sets all variables needed for the cross-compilation. Here is just part of it :

export CONFIG_SITE=~/workspace/eldk-5.4/powerpc/site-config-powerpc-linux
export CC="powerpc-linux-gcc  -m32 -mhard-float --sysroot=~/workspace/eldk-5.4/powerpc/sysroots/powerpc-linux"
export CXX="powerpc-linux-g++  -m32 -mhard-float --sysroot=~/workspace/eldk-5.4/powerpc/sysroots/powerpc-linux"
export CPP="powerpc-linux-gcc -E  -m32 -mhard-float --sysroot=~/workspace/eldk-5.4/powerpc/sysroots/powerpc-linux"
export AS="powerpc-linux-as "
export LD="powerpc-linux-ld  --sysroot=~/workspace/eldk-5.4/powerpc/sysroots/powerpc-linux"
export GDB=powerpc-linux-gdb

If I do source environment-setup-powerpc-linux, all environment variables are imported into the current shell session, and I can compile my example.

Is it possible to import these variables in cmake? If yes, how?


A bit more details :

  1. I am using ELDK v 5.4, and it's install script generates a script which sets all environment variables
  2. I found this tutorial, which explains how to manually set for cross-compilation, but not how to use the script, which sets everything
  3. if I call the script before setting cmake, all works fine, and I can cross-compile, but I'd like that cmake calls the script

Solution

  • Reading through the cmake quick start, you can specify variable on a command line:

    cmake -DVARIABLE1=value1 -DVARIABLE2=value2 ...
    

    Otherwise, set command in the cmake script is probably what you want, see the reference manual. To set the environment variable PATH, do:

    set(ENV{PATH} "/home/martink")
    

    To set normal variable, do:

    set(variable "value")
    

    Not sure which ones you have to set, probably the environment ones.

    That said, setting environment variable prior to calling cmake is often the easiest solution to solve the problem. If you want a cross-platform way to do this that doesn't depend on the syntax of a specific shell to set environment variables, there is the cmake -E env command.