Hi Dmitrii, > Building shared libraries which depend upon > other libraries breaks whenever a dependency found (by something like > AC_SEARCH_LIBS) was not built with -fPIC (or whatever > the name of this option might be on the platform in question). > And, preferably, one might want to check that the dependency is > a dynamic library itself. > > Are there any gnulib (or autoconf) macros available which can help here?
None that I know of. You might get better feedback from a libtool mailing list than from here. But my understanding is that 1) Static libraries are generally built without -fPIC. Building static libraries with -fPIC was commonly done in the 1990ies, because ELF and its dependency mechanisms were not in use everywhere at that time. Since the time shared libraries work fine, there is hardly any use any more to position-independent static code (except, of course, on systems where everything is compiled with -fPIE). 2) libtool adds an option --with-pic to the generated configure script of a package. But hardly anyone makes use of it. 3) Many packages come only with a shared library, not with a .a file any more. See: $ ll /usr/lib/x86_64-linux-gnu/lib*.so | wc -l 422 $ ll /usr/lib/x86_64-linux-gnu/lib*.a | wc -l 207 The reason is that distros prefer shared libraries: When there is a bug fix to a package, they have to rebuild that one package and not also a dozen of other packages. 4) On x86, it was possible to put non-PIC code into a shared library, and that worked (albeit with a performance hit). On x86_64, this does not work any more. And despite of that, the fact that most static libraries are not built with -fPIC does not hurt anyone (apparently). > Thinking of writing such a macro myself I think it would not really be useful. Your time is better spent in making all packages that currently ship only a static library ship a shared library as well. Bruno
