Question

I am using libtool 2.2.6b on ubuntu lucid, and libtool 2.4.2 on ubuntu precise. On lucid my project will link properly. On precise it fails to link. Here’s example code that demonstrates my problem;

configure.ac

AC_INIT([ltp], [0.0.1], [someone])
AM_INIT_AUTOMAKE
AC_CONFIG_HEADERS([config.h])
AC_CONFIG_MACRO_DIR([.m4])
AC_CONFIG_FILES([Makefile foo/Makefile bar/Makefile wah/Makefile])
AC_PROG_CXX
AC_PROG_LIBTOOL
AM_SANITY_CHECK
AC_LANG_CPLUSPLUS
AC_OUTPUT

Makefile.am

SUBDIRS = foo bar wah
ACLOCAL_AMFLAGS = -I .m4

foo/Foo.h

#ifndef FOO_FOO_H_
#define FOO_FOO_H_
namespace Foo
{
  class Foo
  {
  public:
    Foo(long l);
  private:
    long l;
  };
}
#endif

foo/Foo.cpp

#include "foo/Foo.h"
namespace Foo
{
  Foo::Foo(long l) : l(l) {}
}

foo/Makefile.am

lib_LTLIBRARIES = libfoo.la
libfoo_la_SOURCES = Foo.cpp
libfoo_la_CPPFLAGS =
libfoo_la_LDFLAGS = -release 0.0.1
libfoo_la_LIBADD =

bar/Bar.h

#ifndef BAR_BAR_H_
#define BAR_BAR_H_
#include "foo/Foo.h"
namespace Bar
{
  class Bar
  {
  public:
    Bar(const Foo::Foo & f);
  private:
    Foo::Foo f;
  };
}
#endif

bar/Bar.cpp

#include "bar/Bar.h"
namespace Bar
{
  Bar::Bar(const Foo::Foo & f) : f(f) { }
}

bar/Makefile.am

lib_LTLIBRARIES = libbar.la
libbar_la_SOURCES = Bar.cpp
libbar_la_CPPFLAGS =
libbar_la_LDFLAGS = -release 0.0.1
libbar_la_LIBADD = -L../foo -lfoo

wah/main.cpp

#include "bar/Bar.h"
int main(int argc, char * argv[])
{
  Bar::Bar( 5 );
  return 0;
}

wah/Makefile.am

bin_PROGRAMS = wah
wah_SOURCES = main.cpp
wah_CPPFLAGS =
wah_LDADD = -L../bar -lbar

On Lucid, wah links, on Precise, it fails with:

wah/main.cpp:5 undefined reference to `Foo::Foo::Foo(long)'

I can fix this by adding -L../foo -lfoo to wah_LDADD, but really, isn’t libtool supposed to do that for me automagically? The libtool manual section on `Linking executables’ seems to indicate that is exactly what it should do.

Answer 1

On any Debian machine I use for development, I have to compile and install Libtool by hand, because the Debian-supplied version is patched and ignores dependencies in a way that break my builds.

If Ubuntu’s version is similar, you might want to install Libtool from source too.