On 2014-04-23 22:40+0200 Alexander Neundorf wrote:
On Wednesday, April 23, 2014 13:21:39 Alan W. Irwin wrote:
On 2014-04-23 13:21-0400 Bill Hoffman wrote:
On 4/23/2014 12:22 PM, Alan W. Irwin wrote:
However, if you discover the problem is a general one for
--find-package and Qt5, then it appears that Qt5 might be a good
illustrative example to use for your renewed effort at developing a
reliable --find-package capability.
I recently ran into a project using --find-package and found a limitation
that could be very problematic. If a find module in CMake uses a
try-compile, or tries to figure out anything to do with the compiler, this
command will fail. I am not sure there is a good way around this.
Certainly try-compile is not actively discouraged in the CMake Modules, so
this can be added to any module at any time, breaking --find-package in
the
future.
Hi Bill:
You cannot use --find-package unless you specify the language. So I
assume that --find-package enables the specified language, and, in
general, you would think that try-compile would work properly under
those circumstances.
No.
It doesn't really enable a language, it only loads a bunch of files to set the
most urgently required variables.
Most of it is implemented in CMakeFindPackageMode.cmake
It is basically wrapping a find_package() call, setting up just enough to make
it succeed usually.
try_compile() will fail.
My plan was to limit this mode to Config.cmake files only, but as I said, due
to the changes in CMake this has become too much work, so I won't work on that
in the forseeable future.
Hi Alex:
The question that remains is will --find-package be maintained
indefinitely for CMake-3.x? As I said, --find-package is the only way
I know how to obtain required compile and link flags for Qt5 at the
present time (assuming the patch for the library name screwup is
accepted for the CMake support files in Qt5, but that is a separate
Qt5 issue compared to whether or not you decide to maintain
--find-package for CMake-3.x). Until I discovered this thread, I had
assumed that the --find-package option would be maintained
indefinitely for CMake so I haven't looked further at other
alternatives yet.
Assuming you or someone else decides to remove the --find-package
capability now or sometime during CMake-3.x (which from my point of
view makes sense if you are not going to maintain it), then I am going
to look at target properties (for the PLplot libraries that are linked
to Qt5) to see if that gives me the raw compile and link flag
information that I need in a future-proof way.
Alan
__________________________
Alan W. Irwin
Astronomical research affiliation with Department of Physics and Astronomy,
University of Victoria (astrowww.phys.uvic.ca).
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
__________________________
--
Powered by www.kitware.com
Please keep messages on-topic and check the CMake FAQ at:
http://www.cmake.org/Wiki/CMake_FAQ
Kitware offers various services to support the CMake community. For more
information on each offering, please visit:
CMake Support: http://cmake.org/cmake/help/support.html
CMake Consulting: http://cmake.org/cmake/help/consulting.html
CMake Training Courses: http://cmake.org/cmake/help/training.html
Visit other Kitware open-source projects at
http://www.kitware.com/opensource/opensource.html
Follow this link to subscribe/unsubscribe:
http://public.kitware.com/cgi-bin/mailman/listinfo/cmake-developers
