Re: Controlling the linking of shared libraries

[Simon Wright <simon@pushface.org>]

Stephen Leake <stephen_leake@stephe-leake.org> writes:

> Björn Persson <bjorn@xn--rombobjrn-67a.se> writes:
>
>> Does anyone know how to pass command line parameters to Gnatmake and
>> GPRbuild that they should forward to gcc when they invoke gcc as a
>> linker to build a shared library? -largs seems to be used only when a
>> program is linked. When a shared library is linked it seems to be
>> ignored.
>
> Read chapters 11.12 "GNAT Project Manager | Library Projects" and 19
> "GNAT and Libraries" of the GNAT User manual.

I did this and it took me a *long* time to see that you need
Linker'Linker_Options.

This is a subset of one I'm working on:

   with "tash_options";

   project Tashlib is

     for Library_Name use "tash";
     for Library_Kind use "static";
     for Library_Dir use "lib";
     for Source_Dirs use ("include");
     for Externally_Built use "true";

     package Linker is
        for Linker_Options use Tash_Options.Library_Options;
     end Linker;

   end Tashlib;

and

   project Tash_Options is

      for Source_Dirs use ();

      Library_Options :=
        (
         "-L/usr/lib",
         "-ltk8.5",
         "-ltcl8.5"
        );

   end Tash_Options;

The resulting link for a program using tashlib.gpr is

   $ gnatmake -P tash_tests.gpr tashtest.adb
   gnatbind -E -I- -x /Users/simon/sf/tcladashell/tests/.build/tashtest.ali
   gnatlink /Users/simon/sf/tcladashell/tests/.build/tashtest.ali -g \
     -L/Users/simon/sf/tcladashell/lib/ -ltash \                     <<<<a
     -Wl,-rpath,/opt/gcc-4.6.0......./4.6.0/adalib/ \
     -L/usr/lib -ltk8.5 -ltcl8.5 \                                   <<<<b
     -o /Users/simon/sf/tcladashell/tests/tashtest

where the part I've marked 'a' comes from the main part of tashlib.gpr
and the part marked 'b' comes from Tashlib.Linker'Linker_Options.

Note that this all works fine for static libraries, in spite of what you
might have expected from the documentation; the only thing missing is
that if you create a stand-alone library (SAL) the source files will be
copied to the right place, whereas for this static library I have to do
it in the Makefile.