Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!sdd.hp.com!wuarchive!udel!princeton!pucc!BVAUGHAN
From: BVAUGHAN@pucc.Princeton.EDU (Barbara Vaughan)
Newsgroups: comp.lang.fortran
Subject: Re: Externals and Block Data
Message-ID: <12010@pucc.Princeton.EDU>
Date: 6 Nov 90 22:47:38 GMT
References: <28325@shamash.cdc.com>
Reply-To: BVAUGHAN@pucc.Princeton.EDU
Organization: Princeton University, NJ
Lines: 35
Disclaimer: Author bears full responsibility for contents of this article

In article <28325@shamash.cdc.com>, ddh@hare.cdc.com (Dan Horsfall) writes:
>Problem: How to load a BLOCK DATA subprogram from a LIBRARY.
>    (This can be a problem since you can't CALL a block data subprogram
>    in the usual sense, thus the loader/linker process ofmatching
>    external references to entry points frequently does not work.)
>
I believe the original question here involved an unresolved external in
a program compiled using an old version of MS Fortran.  I didn't realize
that a BLOCK DATA subroutine was involved or I would have responded
sooner.  I learned that there was some kind of bug in MS-Fortran handling
of BLOCK DATA subroutines.  (MS tech support called it an 'instability'.)
I haven't used MS Fortran in a long time, but here is a note from my
files.
       (5) Note to programmers: This diskette contains an execution
      module which should run on most DOS systems. It should not be
      necessary to recompile the program. If for some reason the
      program must be recompiled, the following precaution should be
      heeded. MM contains a BLOCK DATA subroutine
      which, because of a peculiarity in version 3.2 of MS-FORTRAN,
      must be stored in a separate file, compiled separately, and
      must precede the main program in the LINK phase. Both the source
      and object code files for this subroutine are included (MMBLOCK.FOR
      and MMBLOCK.OBJ). Earlier or later releases of MS-FORTRAN may not
      require this precaution, in which case MMBLOCK may be added to
      the source file MMPC.FOR. Check with MICROSOFT technical support
      for details. Failure to compile and link as described here causes
      peculiar errors during execution which appear to be unrelated to
      the BLOCK DATA subroutine.

When I say 'must precede the main program in the link phase', I mean that
when you list the names of the object code files, you put the file
containing the BLOCK DATA subroutine first in the list.  I hope this
helps.

Barbara Vaughan