Re: GNAT and subunits

[stt@spock.camb.inmet.com (Tucker Taft)]

Philip Brashear (brashear@ns1.sw-eng.falls-church.va.us) wrote:

: ...
: Is GNAT's processing of subunits really in accordance with language rules?
: More importantly, is it in accordance with the spirit and intent of separate
: compilation?

: Here's my problem:  I have a program (Prog) with a subunit (procedure Sub).
: When I compile Prog, GNAT requires me to provide a file containing Sub.  OK,
: I can live with that -- I'll just provide a stub.  So, compiling shows me
: that my interfaces are pretty much correct.  I link and execute.

: Now, I complete Sub (in the file Prog-Sub.adb).  If I just submit Prog-Sub.adb 
: to the compiler (as is my usual habit, and, I think, the common way of doing
: things), I get the usual "No code generated ... " message.  I now link and
: execute.  Guess what!  The STUB version of Sub is still used!  That is, 
: re-compiling the separate subprogram (alone) does not appear to affect the
: "library".

This sounds like a bug.  Unfortunately, it is a bit hard to know
because it may depend on what you mean by "submit" a file to GNAT.

: Can someone convince me that this is OK?

No, it sounds like a bug, unless your notion of what it means to "submit"
a file to GNAT disagrees with their notion.  The key principle in GNAT
is that the sources are what matters.  If you update a source file,
then at link-time, it should provide a mode where it complains
if the sources and the object modules are inconsistent.

: Can someone convince me that this is a GOOD THING?

I would put your energy into getting the GNAT folks to fix the bug.
I presume you have already tried gnat-report@cs.nyu.edu ...

: Phil Brashear
: brashepw@msrc.wpafb.af.mil
: brashear@sw-eng.falls-church.va.us

-Tucker Taft  stt@inmet.com
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