Re: problem using the .a libs ...

[Roberto Alejandro Espí Muñoz]

I reordered the link declaration of the .a libs and it worked !!! Thanks a
lot ... I noticed that I have now a ciclic dependency with two libs, and
tried to declare them twice but I didn't manage to resolve it ...  How can I
declare them so that their interdependencies aren't a problem when linking
??

Thanks ....

On Dec 10, 2007 4:43 PM, Kamaljit Singh <address@hidden> wrote:

> The way the .a work is that if a undefined symbol is defined by a .o in
> the .a
> then only the .o is linked in otherwise it isnt linked in. But when you do
> *.o
> then you link in all .o's regardless.
>
> The .o's in the .a are evaluated as they are seen hence they'll not be
> revisited
> in case a later .o leads to an undefined symbol that maybe defined by an
> earlier
> seen .o (from the same .a) but had been deemed to be unimportant and left
> out.
>
> Some of the following solutions may work for you -
> 1. Ensure the correct order in the .a -- maybe erroneous in the long run.
> 2. Have the .a twice on the link line - may just work.
> 3. You could use -Wl, --whole-archive libxx.a --Wl,--no-whole-archive (for
> linux).
>     This'll be identical to linking all .o, regardless. Maynot all that
> portable.
> 4. Have a "-u foo" on the link line so that if some .o defines the symbol
> "foo"
>     it'll always be linked in. For this you'll need to know more about the
> code to
>     ensure the "correctness".
>
> kamaljit
>
>
> *Roberto Alejandro Espí Muñoz <address@hidden>* wrote:
>
> Hi !! I tried building my project using the example from the automake
> documentation in which i *_LDADD* the static libs in the compilation
> process. My project has about 10 directories and in each one I have
> something like this:
>
> directoryX/Makefile.am:
> elementos = file1.cpp file2.cpp
>
> noinst_LIBRARIES = libDirectoryX.a
> libDirectoryX_a_SOURCES = \
> $(elementos)
>
> AM_CXXFLAGS = ...
> AM_LDFLAGS = ...
>
> Each X is a number .. directory1, directory2 ... etc ...
>
> In the root directory of my project I have this Makefile.am
>
> link_objects_a = \
> directory1/libDirectory1.a directory2/libDirectory2.a
> directory3/libDirectory3.a ... and so on ...
>
> SUBDIRS = ./directory1 ./directory2 ./directory3 ... and so on ...
>
> bin_PROGRAMS = program
>
> program_SOURCES = main.cpp
> program_LDADD = $(link_objects_a)
>
> program_CXXFLAGS = ......
> program_LDFLAGS = .......
>
> I get an error of undefined functions in some of the libDirectoryX.a's
> with
> functions from another libDirectoryX.a. The funny thing is that it only
> happens when I use this notation of *directoryX/libDirectoryX.a *for all
> my
> directories. If I use the *directoryX/*.o* notation on the libDirectoryX.a
> 's
> that give me the problem, the error disappears.
>
> Can anyone tell me if they've had any similar problems?? or none at all??
> --
> teratux
> ------------
> http://teratux.blogspot.com
>
>
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------------
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