Handling Missing X Libs Better

[Alexander Neundorf]

On Tuesday 27 February 2007 21:56, Allen Winter wrote:
> On Tuesday 27 February 2007 3:42:22 pm Alexander Neundorf wrote:
> > On Tuesday 27 February 2007 19:20, Allen Winter wrote:
> > > Howdy,
> > >
> > > Here's a problem with the buildsystem that I hope a cmake guru can fix.
> > > A least twice I've had to help people on $kde4-devel with the following
> > > scenario:
> > >
> > > - user runs cmake && make
> > > - compile fails due to missing ICE include files
> > > - user installs their distros libICE-devel packages
> > > - user runs cmake && make
> > > - linking fails (can't find libICE)
> > >
> > > apparently the fact that libICE can't be found is cached.
> > > so the user needs to remove their cmake cache so the
> > > search for libICE is re-run and then added to the linker libs list.
> > >
> > > Should there be an error exit from cmake if libICE can't be found
> > > in the first place?
> >
> > Where does this happen ?
>
> Alex,
>
> You're forcing me to not be lazy :)
>
> OK, in FindX11.cmake we see
>     CHECK_LIBRARY_EXISTS("ICE" "IceConnectionNumber" "${X11_LIBRARY_DIR}"
>                          CMAKE_LIB_ICE_HAS_ICECONNECTIONNUMBER)
>     if (CMAKE_LIB_ICE_HAS_ICECONNECTIONNUMBER)
>       set(X11_X_PRE_LIBS -lSM -lICE)
>     endif (CMAKE_LIB_ICE_HAS_ICECONNECTIONNUMBER)
>
> If not found, then you'll have in CMakeCache.txt:
> MAKE_LIB_ICE_HAS_ICECONNECTIONNUMBER:INTERNAL=0
> and cmake continues normally.
>
> then the compile starts and errors when you encounter a file that
> looks for an ICE include file.
>
> then you realize you need the libICE devel package, so you install it.
>
> then you run cmake again, but CHECK_LIBRARY_EXISTS("ICE".... ) apparently
> looks at the cache value of CMAKE_LIB_ICE_HAS_ICECONNECTIONNUMBER
> so you'll never have "-lSM -lICE" added to your X11_LIBS

That feels more like a bug in the cmake module. If the test wasn't successfull 
it should try again the next time. Apparently it doesn't.
I'll have a look.

Bye
Alex
-- 
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