linuxcompilationstatic-librariesstatic-linkinglibtool

Why libtool runs ranlib for a static library installation?

I'm trying to understand why libtool runs ranlib when installing a static library. This is an example from the link: https://www.gnu.org/software/libtool/manual/html_node/Installing-libraries.html

$ libtool --mode=install cp libhello.la /usr/local/lib/libhello.la
cp libhello.la /usr/local/lib/libhello.la
cp .libs/libhello.a /usr/local/lib/libhello.a
ranlib /usr/local/lib/libhello.a

But, isn't the index table already created and shouldn't it be just a simple copy operation? I found running ranlib at the end of the copy redundant as the library already has an index.

Thanks.

Solution

  • Back in the bad old days, ar did not create an index.

    libtool is intended to run on a variety of systems, some of which have an index-creating ar and some don't.

    For compatibility's sake, it still invokes ranlib to create the index after installing the static library.