Check CMake Cache Variable in Toolchain File

cmake

Solution

I don't pretend to fully understand what's going on behind the scenes, but here's a workaround that works for me:

# Problem: CMake runs toolchain files multiple times, but can't read cache variables on some runs.
# Workaround: On first run (in which cache variables are always accessible), set an intermediary environment variable.

if (FOO)
    # Environment variables are always preserved.
    set(ENV{_FOO} "${FOO}")
else ()
    set(FOO "$ENV{_FOO}")
endif ()

Problem

I'm having trouble setting a configuration variable via the command line. I can't determine it from the system, so I expect the user to specify: ``` cmake -DCMAKE_TOOLCHAIN_FILE=../android.toolchain -DANDROID_ABI:STRING="arm64" .. ``` Inside my `android.toolchain`, I have the following: ``` message(STATUS "Android ABI: ${ANDROID_ABI}") if( "${ANDROID_ABI}" STREQUAL "" ) message(FATAL_ERROR "Please specifiy ABI at cmake call -DANDROID_ABI:STRING=armeabi or -DANDROID_ABI:STRING=arm64") endif() ``` No matter what, it fails at this line EVEN THOUGH it prints out the correct arm64: ``` -- Android ABI: arm64 CMake Error at yaml-cpp/android.toolchain:45 (message): Please specifiy ABI at cmake call -DANDROID_ABI:STRING=armeabi or -DANDROID_ABI:STRING=arm64 ``` Could anyone direct me to what I'm doing wrong? I think this has to do with: - -D adds a cache variable instead of a normal variable - This is in a toolchain file... it seems to ignore cache variables Any thoughts or suggestions?

Original source