On 2019-03-15 23:10+0100 Rolf Eike Beer wrote:
Out of boredom I'm hacking a bit around in the build system of Subsurface
(https://github.com/Subsurface-divelog/subsurface). One of the things I'm
looking to is requiring a newer CMake version. And now something strange
happens:
The original code:
cmake_minimum_required(VERSION 2.8.11)
This still works:
cmake_minimum_required(VERSION 3.0)
like this:
-- Found PkgConfig: /usr/bin/pkg-config (found version "0.26")
-- Checking for module 'libxml-2.0'
-- Found libxml-2.0, version 2.9.4
-- Checking for module 'sqlite3'
-- Found sqlite3, version 3.20.1
-- Checking for module 'libxslt'
-- Found libxslt, version 1.1.29
-- Checking for module 'libzip'
-- Found libzip, version 1.1.3
And this breaks:
cmake_minimum_required(VERSION 3.1)
like this:
-- Found PkgConfig: /usr/bin/pkg-config (found version "0.26")
-- Checking for module 'libxml-2.0'
-- Found libxml-2.0, version 2.9.1
-- Checking for module 'sqlite3'
-- Found sqlite3, version 3.8.2
-- Checking for module 'libxslt'
-- Found libxslt, version 1.1.28
-- Checking for module 'libzip'
-- No package 'libzip' found
I suspected it was a policy thing, so I tried this:
foreach(_p RANGE 21 54)
cmake_policy(SET CMP00${_p} OLD)
endforeach()
Does not change anything.
Build logs can be found here for 3.0:
https://api.travis-ci.org/v3/job/506938155/log.txt
And for 3.1:
https://api.travis-ci.org/v3/job/506849909/log.txt
It's a CMake 3.8.2 actually, which can be found in the mxe tarballs (look in
the logs, IIRC it's the first one).
Has anyone an idea what's happening there? And even more important: how to get
it fixed? The maximum version the requirement can be raised to is 3.5.1 for
the moment because of the supported Ubuntu versions (16.04+).
Hi Eike:
Since you appear to be running 3.8.2 in both cases, then the default
policy change difference between cmake_minimum_required(VERSION 3.0)
and cmake_minimum_required(VERSION 3.1) should be the only difference
between the two results. So you appear to be left with (i)
cmake_minimum_required is not implemented as documented (i.e., there
is more going on then just a policy change for CMake 3.8.2), (ii)
there is some typo in how you changed policies for
cmake_minimum_required(VERSION 3.1) to be effectively the same as the
default policies for cmake_minimum_required(VERSION 3.0), or (iii)
there is absolutely no explanation for what you have found. :-)
However, if it were me I would simply forget about getting to the
bottom of this mystery for cmake_minimum_required(VERSION 3.1) since
that is a really an old set of policies. Instead, I suggest you move
on to the more modern set of policies associated with
cmake_minimum_required(VERSION 3.5.1) to see whether you have the same
trouble in that case for a range of CMake versions (including 3.8.2,
just in case there is a specific bug in that version) from 3.5.1 to
the latest version.
Alan
__
Alan W. Irwin
Programming affiliations with the FreeEOS equation-of-state
implementation for stellar interiors (freeeos.sf.net); the Time
Ephemerides project (timeephem.sf.net); PLplot scientific plotting
software package (plplot.sf.net); the libLASi project
(unifont.org/lasi); the Loads of Linux Links project (loll.sf.net);
and the Linux Brochure Project (lbproject.sf.net).
__
Linux-powered Science
__
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