[CMake] Resetting CMAKE_Fortran_FLAGS for a specific file

[Glenn Coombs]

In my opinion this is a deficiency in how cmake currently works with object
libraries.  If one of the source files in an object library depends on a
third library then it should be possible to specify that in the link
interface of either the object library or the source file.  It is wrong to
have to specify the dependency multiple times for every library or
executable that uses the object library.  It is a property of the object
library, not the users of the object library.

I believe there is already a enhancement request open for something like
this.

--
Glenn



On 13 August 2014 15:44, marco restelli <mrestelli at gmail.com> wrote:

> 2014-08-13 16:16 GMT+0200, Mark Abraham <mark.j.abraham at gmail.com>:
> > On Wed, Aug 13, 2014 at 7:12 AM, marco restelli <mrestelli at gmail.com>
> > wrote:
> >
> >> 2014-08-13 15:53 GMT+0200, Mark Abraham <mark.j.abraham at gmail.com>:
> >> > On Wed, Aug 13, 2014 at 3:18 AM, marco restelli <mrestelli at gmail.com>
> >> > wrote:
> >> >
> >> >> Hi Petr,
> >> >>    thanks, very informative!
> >> >>
> >> >> 2014-08-13 9:20 GMT+0200, Petr Kmoch <petr.kmoch at gmail.com>:
> >> >> > Hi Marco.
> >> >> >
> >> >> > Sane compilers allow later command-line options to override earlier
> >> >> > ones,
> >> >> > so what you're doing should be fine. Unfortunately, I know some
> >> Fortran
> >> >> > compilers are not sane in this regard.
> >> >>
> >> >> Here, I would really like to reduce as much as possible the flags
> >> >> regardless of the chosen compiler, so "undoing" the chosen flags
> >> >> seems to me cumbersome and compiler dependent, compared to resetting
> >> >> them altogether. I like the idea of OBJECT libraries better (it also
> >> >> solves other problems I have, I did not know about it!).
> >> >>
> >> >> > If you really need to solve this by explicitly modifying the global
> >> >> > list
> >> >> > for a particular file, the only thing I can think of is move those
> >> >> > files
> >> >> to
> >> >> > a separate CMakeList and turn them into an object library:
> >> >>
> >> >> This almost works, I have a problem specifying liking dependencies
> for
> >> >> the OBJECT libraries. With a normal library, I can use
> >> >>
> >> >> TARGET_LINK_LIBRARIES( my_library ${other_libs_my_library_depends_on}
> >> >> )
> >> >>
> >> >> but if my_library is OBJECT I see the error
> >> >>
> >> >>   Object library target "my_library" may not link to anything.
> >> >>
> >> >
> >> > See http://www.cmake.org/cmake/help/v3.0/command/add_library.html for
> >> the
> >> > correct way to do things with object libraries - for this purpose,
> they
> >> are
> >> > closer to source files than libraries, which makes sense given that
> >> there's
> >> > not actually a library written to disk anywhere.
> >>
> >> Mark, thanks, but here I don't find anything that answers my question,
> >> namely specifying that my OBJECT library (i.e. the files included in
> >> it) require other libraries for linking.
> >
> >
> > The object library is never linked, so the issue of linking with it or to
> > it does not arise. The targets that use the object library have
> transitive
> > linking dependencies, just like you had if the source files in the object
> > library had been directly specified as part of those targets.
>
> OK, let me see if I understad it. Using the example in
>
> http://www.cmake.org/Wiki/CMake/Tutorials/Object_Library
>
> let us say I have
>
>
> # A/CMakeLists.txt
> add_library(A OBJECT ${A_srcs})
>
> # B/CMakeLists.txt
> add_library(B OBJECT ${B_srcs})
>
> # CMakeLists.txt
> add_subdirectory(A)
> add_subdirectory(B)
> add_library(big ${other_srcs} $<TARGET_OBJECTS:A> $<TARGET_OBJECTS:B>)
>
>
> and I know that whenever I link the files listed in ${A_srcs}, i.e.
> whenever I likd the OBJECT library A, I also need to link
> libsomeotherlibrary.a . Then in the main CMakeLists.txt I add
>
> TARGET_LINK_LIBRARIES( big someotherlibrary )
>
> right?
>
>
> Moreover, there is no way to specify someotherlibrary in
> A/CMakeLists.txt, it has to be done where I define the target big,
> namely in the main CMakeLists.txt. Is this correct?
>
>
> Thanks,
>    Marco
> --
>
> 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/mailman/listinfo/cmake
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://public.kitware.com/pipermail/cmake/attachments/20140814/70e3d8a1/attachment-0001.html>