[Python-Dev] readline not getting built when .so symlink doesn't exist

Michael Hudson mwh@python.net
04 Jun 2001 19:05:10 +0100

Skip Montanaro <skip@pobox.com> writes:

> I recently upgraded to Mandrake 8.0.  I find that the readline
> module is no longer getting built.  When building, it builds rgbimb
> followed immediately by crypt.  Readline, which is tested for in
> between, is not built.  Apparently, it can't find one of the
> libraries required to build it.  On my system, both readline and
> termcap are in /lib.  Neither has a static version available and
> neither as a plain .so file available.  The .so file always has a
> version number tacked onto the end:
>     % ls -l /lib/libtermcap* /lib/libreadline*
>     lrwxrwxrwx    1 root     root           18 May 29 10:53 /lib/libreadline.so.4 -> libreadline.so.4.1
>     -rwxr-xr-x    1 root     root       152440 Mar 25 01:26 /lib/libreadline.so.4.1
>     lrwxrwxrwx    1 root     root           19 May 29 10:53 /lib/libtermcap.so.2 -> libtermcap.so.2.0.8
>     -rwxr-xr-x    1 root     root        11608 Mar 26 10:32 /lib/libtermcap.so.2.0.8
> If I create the necessary .so symlinks it builds okay.
> Perhaps this is a bug in Mandrake 8.0 (it wouldn't be the first
> one), but if it is valid for shared libraries to be installed with
> only a version-numbered .so file, then it seems to me that distutils
> ought to handle that.

Hmm.  Does compiling a proggie

$ gcc foo.c -lreadline 

work?  It doesn't here if I move libreadline.so & libreadline.a out of
the way.

If the C compiler isn't going to find readline, there ain't much point
distutils trying to find it...

> There are several programs in /usr/bin on my machine that seem to be
> dynamically linked to libreadline.  

Those things will be directly linked to libreadline.so.whatever; I
believe the libfoo.so files are only for the (compile time) linker's

> In addition, /usr/lib/python2.0/lib-dynload/readline.so exists,
> which suggests that the .so-without version number is valid as far
> as ld is concerned.

ld != ld.so.

Do you need a readline-devel package or something?


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