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Re: lib-link.m4: AC_LIB_LINKFLAGS_BODY: --without-libFOO-prefix?


From: Simon Josefsson
Subject: Re: lib-link.m4: AC_LIB_LINKFLAGS_BODY: --without-libFOO-prefix?
Date: Sat, 27 Aug 2005 15:03:05 +0200
User-agent: Gnus/5.110004 (No Gnus v0.4) Emacs/22.0.50 (gnu/linux)

Bruno Haible <address@hidden> writes:

> Simon Josefsson wrote:
>> What is the point of this configure parameter?
>>
>> I understand that --with-libFOO-prefix is used to set the prefix that
>> make the macro search in $prefix/include and $prefix/lib to find
>> libFOO.
>>
>> Specifically, what is the difference between not supplying
>> --without-libFOO-prefix and supplying it?
>
> By default, the AC_LIB_LINKFLAGS_BODY macro will search in $prefix/include
> and $prefix/lib, where $prefix is given through the --prefix option.
> This is needed for the quite frequent use of people that build many
> GNU packages into the same $prefix directory.
>
> By specifying --without-libFOO-prefix you disable this search directory,
> so that the search will only consider /usr/include and /usr/lib (and
> possibly others that the compiler uses, through CPPFLAGS etc.).

Aha!  I see.  That seems like a good idea.

>> Further, does this macro handle 64-bit libraries in $prefix/lib64?
>
> No. Excellent point. I need to work on that. Is there a standard convention
> that would tell me whether to look in lib or lib64? Seems to be OS dependent,
> CPU dependent (seen on x86_64 and sparc64 but not on alpha), and compiler
> mode dependent (whether sizeof(long) == 8 or == 4), no?

Yes, probably.

FWIW, Libtool's AC_LIBTOOL_SYS_DYNAMIC_LINKER define $libsuff.  I have
no idea whether this result in good behavior or not.

  case $host_os in
  irix5* | nonstopux*)
    libsuff= shlibsuff=
    ;;
  *)
    case $LD in # libtool.m4 will add one of these switches to LD
    *-32|*"-32 "|*-melf32bsmip|*"-melf32bsmip ")
      libsuff= shlibsuff= libmagic=32-bit;;
    *-n32|*"-n32 "|*-melf32bmipn32|*"-melf32bmipn32 ")
      libsuff=32 shlibsuff=N32 libmagic=N32;;
    *-64|*"-64 "|*-melf64bmip|*"-melf64bmip ")
      libsuff=64 shlibsuff=64 libmagic=64-bit;;
    *) libsuff= shlibsuff= libmagic=never-match;;
    esac
    ;;
  esac

Then you can use $libsuff in your configure.ac or lib-link.m4 macro,
e.g.:

        LDFLAGS="$LDFLAGS -L$GSSAPI_ROOT/lib$libsuff -lgssapi"

Thanks,
Simon




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