[CMake] Merge two static libraries

[Marcel Loose]

Hi Eric,

I still don't understand why you want to have just one library. What's
wrong with having a common library, containing all the common software
and a console/window specific library?

You could also use shared libraries (DLLs), but I guess that's out of
the question for you, since you've been talking about static libraries
only.

Best regards,
Marcel Loose.

On Tue, 2010-10-05 at 10:45 +0200, pellegrini wrote:
> in fact the makefile we would like to generate should be able to:
> 
>     - build the console version of library (-DBUILD_WINDOW=False)
>     - build the console AND the window versions of the library 
> (-DBUILD_WINDOW=True)
> 
> this is the latter case that triggered my questions.
> 
> Considering that only 2 files out of 50 will have a different 
> compilation flag between the console and window mode, that
> would be a pity to duplicate the compilation of the 48 common sources 
> files. That's why I was looking for a way to produce:
> 
>     - once the 48 objects files common to console and window building modes
>     - twice the 2 object files specific to the building mode:
>         * once in the console mode
>         * once in the window mode
>     - make a static library for the console mode
>     - make a static library for the window mode
> 
> That's why to do so, I planned to build:
>     - a static library for the 48 common files --> common.a
>     - a static library for the 2 specific files in console mode in which 
> I would have inserted common.a
>     - a static library for the 2 specific files in window mode in which 
> I would have inserted common.a
> 
> but failed to perform the insertion step ...
> 
> Marcel Loose a écrit :
> >>>> On 5-10-2010 at 10:10, in message <4CAADD79.7000801 at ill.fr>,
> >>>>         
> > pellegrini
> > <pellegrini at ill.fr> wrote: 
> >   
> >> Hello everybody,
> >>
> >> I have a library that can be built for a use in different modes 
> >> (console, window). It is made of two sets of files. The first one is
> >>     
> >
> >   
> >> common to
> >>  the console/window building modes while the second set has to be be
> >>     
> >
> >   
> >> built with a slightly different compiler flags depending on the
> >>     
> > selected
> >   
> >> building mode.
> >>
> >> After many discussions here, I was advised to build a static library 
> >>     
> >
> >   
> >> for the the files common to console and window building modes
> >> (e.g. common.a) and to build a second static library for the files 
> >> depending on the building mode (e.g. console.a and window.a) linking
> >>     
> > the
> >   
> >> latter to the first one. I did it and ... it worked ! But what I
> >>     
> > would 
> >   
> >> like is a little bit different. I would like my console.a (or
> >>     
> > window.a) 
> >   
> >> library to
> >> contain the object files of the common.a library. Indeed something
> >>     
> > like 
> >   
> >> 'ar cr console.a library.a'.
> >>
> >> Would you have any idea ?
> >>
> >> thank you
> >>
> >> Eric
> >>     
> >
> > Hi Eric,
> >
> > My first question is: why do you want to join these two libraries. I
> > understand from your mail that people suggested you to create two
> > separate libraries. Now you want to join them again.
> >
> > To answer your question: you can't join two static libraries, not in a
> > portable way. You should specify a complete list of sources in your
> > CMakeLists.txt file for each of the two libraries. Something like:
> >
> > SET(LIB_SOURCES common.c)
> > IF(BUILD_CONSOLE)
> >   LIST(APPEND LIB_SOURCES  console.c)
> >   ADD_LIBRARY(console ${LIB_SOURCES})
> > ELSEIF(BUILD_WINDOW)
> >   LIST(APPEND LIB_SOURCES window.c)
> >   ADD_LIBRARY(window ${LIB_SOURCES})
> > ENDIF(BUILD_CONSOLE)
> >
> > The downside to this solution is that you have duplicates of the object
> > files that are part of common, but that's the price you'll have to pay
> > if you want to have just one static library.
> >
> > HTH,
> > Marcel Loose.
> >   
> 
>