[CMake] Multiple versions of ITK in one build?

[John Drescher]

On Tue, May 28, 2013 at 10:16 AM, Zamir Khan <zamir.khan at gmail.com> wrote:
> We have a project where multiple modules rely on ITK. Most modules have been
> upgraded to ITK 4.31, but one still relies on ITK 3.20 and it would take a
> significant effort to upgrade it. In the meantime, is there a way for us to
> keep these modules under a single top-level CMake and have them use their
> respective versions of ITK?
>
> We thought we could just try to overwrite the ITK_DIR variable in the
> appropriate place, but our first naive implementation of this did not work.
>
> Just wondering if someone has done this and whether it is possible (before
> we dive deeper).
>

On windows I have several completely separate build trees with their
own environment. This way I can build for different compiler versions,
32/64 bit and different versions of libraries like this. Inside the
root of each build tree there is a link to the appropriate Visual
Studio command prompt that has its default folder set to the build
tree root. Also in the root there is a batch file that sets quite a
few _DIR environment variables to help cmake find the correct compiled
libraries. This has worked well for the 5 or so years that I have done
it this way. I do not use INSTALL targets so none of the binaries end
up in Program Files.

John