Re: Idea: Eliminate libf2c/f2c.h installation from g77 entirely?

[Jeffrey A Law <law at cygnus dot com>]

  In message <199804182125.RAA23699@melange.gnu.org>you write:
  > I'm thinking it might be time to eliminate from g77 any and all
  > attempts to "help" the sysadmin by installing the libf2c.a and
  > f2c.h files somewhere, which is currently done so that f2c users
  > "automatically" use the same files as used by g77, making successful
  > linking of executables combining objects generated by both g77 and
  > f2c more likely.
I'm all for it :-)  We quite a few folks complaining about the
installation procedure writing outside of $prefix on the egcs
lists.

Of course, we might get complaints in the other direction after
we make the change.

However, I still feel removing the extra copies of f2c.h and
libf2c.a is the right thing to do.

  > (A short summary of the overall issues: g77 currently uses libf2c,
  > f2c's run-time library, for it's own run-time needs.  It ships with
  > a patched version of libf2c, but we've avoided creating gratuitous
  > incompatibilities in the interface.  That, combined with appropriate
  > effort in g77, allows users to pretty much pick and choose which
  > Fortran modules they compile with g77 and which with f2c, link
  > the objects together, and have things actually work, even including
  > starting I/O in a g77-compiled module and continuing it in an
  > f2c-compiled one.)
Yup.  And I've even taken advantage of this at one point, though
I don't remember why :-)

  >   -  If f2c isn't being used, the only need for f2c.h (which g77
  >      generates its copy of via its configuration process from f2c.h.in,
  >      which in turn is just a modified copy of netlib's f2c's f2c.h)
  >      is when building g77's copy of libf2c.  There is no need to install
  >      this f2c.h anywhere; it's almost like an object file in this
  >      respect, in that, once the build is completed, it isn't needed.
I thought we needed to make sure that someone building a translated
file picked up the right f2c.h.

  >   -  If f2c isn't being used, as long as g77 prefers "its" copy of libf2c.a
  >      (e.g. the one in $prefix/lib/gcc-lib/$machine/$version) over the one
  >      in the system's (/usr/lib) library, libf2c.a need not be installed
  >      anywhere else.  That is, it's really no different than the cc1,
  >      cc1plus, f771, and specs files, AFAIK.
I'm pretty sure that the libf2c.a from libsubdir will be preferred,
but we should double check.



  > Only a sysadmin who cares about g77 and f2c inter-operability will be
  > interested in what we do, and I believe that it'll be safer and more
  > robust, overall, to have g77 just "do its job" and not futz with bits
  > and pieces of f2c installation, leaving it to the sysadmin to do that,
  > as would be described in the g77 docs.
I'd tend to agree.  If we want to make their life easier we might
consider a configure time option to install f2c.h & libf2c.a
in /usr/local/..., regardless of the $prefix option.

I also get the feeling that f2c is becoming less and less important
as g77 continues to move forward and gain wider acceptance.  I can't
think of a reason to use f2c over g77 on the two platforms where I
do most of my work (hppa & x86).


  > So, I'd like to implement this removal, along with the relevant docs,
  > myself in the following release schedule:
  > 
  >   -  For g77, in version 0.5.23, the upcoming version that will also
  >      be the first to be based on gcc 2.8 (instead of gcc 2.7).
  > 
  >   -  For egcs, in version 1.1.
  > 
  > Please let me know if you see any problems with this idea, though
  > I'm also interested in "sounds like a good idea" messages as well.
They both sound good to me.


jeff