[vtk-developers] A single ExternalData folder for multiple variants of VTK. Is it possible?

[Andras Lasso]

OK, then probably there is no simple solution without CMake changes.

However, with a few simple improvements it can be all made to work in Windows:
1. In kwsys implement SystemTools::CreateSymlink for Windows (this would be useful in general)
2. In ExternalData.cmake remove "UNIX AND" from "if(UNIX AND NOT ExternalData_NO_SYMLINKS)..." in _ExternalData_link_or_copy
3. In ExternalData.cmake set ExternalData_NO_SYMLINKS to TRUE by default on Windows (or maybe do a build-time check for SystemTools::CreateSymlink and set ExternalData_NO_SYMLINKS to TRUE by default only if the check fails)

This would allow symlinking on Windows for anybody who is concerned about disk space.

Andras 

-----Original Message-----
From: Brad King [mailto:brad.king at kitware.com] 
Sent: July 15, 2016 9:46
To: Andras Lasso <lasso at queensu.ca>; Andrew Maclean <andrew.amaclean at gmail.com>
Cc: VTK Developers <vtk-developers at vtk.org>
Subject: Re: [vtk-developers] A single ExternalData folder for multiple variants of VTK. Is it possible?

On 07/15/2016 09:41 AM, Andras Lasso wrote:
> You can create symlinks in Windows

Yes, but as you point out it is basically useless for applications in general due to lack of permissions.

> you should be able to set up shared external directory manually.

Every individual file needs to be linked with a specific name in the build tree that is unrelated to its name in the object store.  This is not practical to do manually.

-Brad