Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!tut.cis.ohio-state.edu!cwjcc!hal!ncoast!allbery
From: allbery@ncoast.ORG (Brandon S. Allbery)
Newsgroups: comp.unix.wizards
Subject: Re: stdout (was What "isatty"?)
Message-ID: <13692@ncoast.ORG>
Date: 3 Jun 89 18:07:20 GMT
References: <19756@adm.BRL.MIL> <17796@mimsy.UUCP>
Reply-To: allbery@ncoast.UUCP (Brandon S. Allbery)
Followup-To: comp.unix.wizards
Organization: Cleveland Public Access UN*X, Cleveland, Oh
Lines: 48

As quoted from <17796@mimsy.UUCP> by chris@mimsy.UUCP (Chris Torek):
+---------------
| In some article whose referent is gone because Root Boy gets this stuff
| via a mailing list rather than netnews, I wrote:
| >>Programs that produce output should produce the output to stdout.
| 
| In article <19756@adm.BRL.MIL> rbj@dsys.icst.nbs.gov (Root Boy Jim) writes:
| >I agree completely, Chris. Now get cracking on `cc', so that
| >`cc prog.c' writes to stdout instead of `a.out' :-)
| 
| As you can see by the `:-)' sign, Jimmy C. is kidding.  But there is
| much truth in this.  The C compiler should write to stdout, unless
| there is some overriding reason that it cannot---and in fact, the
+---------------

Just to be obnoxiously pedantic [ ;-) ]:  "cc" doesn't write to a.out; "ld"
does.  This doesn't mean that "cc" and "ld" aren't atrociously implemented,
however.

The problem with "cc" is that it's a (supposedly) "smart" wrapper for the
compiler, assembler, and linker; it knows about filename extensions so it
can decide whether to pass something to /lib/ccom, as, or ld (and under
System III and -- I hear -- SunOS4.0, it complains if it doesn't recognize
the extension of a file).  Yucch.  If I want that, I'll use "make", where I
can define the program to use as I see fit.

I'd prefer that "cc" build the pipeline to cpp, ccom, and c2/optim/copt/
whatever-it's-called-on-system-xyzzy, then write the resulting assembly code
to stdout; then the casual user can pipe that to "as", or let the Makefile
deal with it (that being what "make" is for).  "ld" is more similar to an
archive maintenance utility than to a filter, but it could still do its
seeking in a temporary file and write the resulting binary to stdout... and
for a trivial (one object module, no libraries other than -lc) binary it
could easily be modified to be used as "cc < foo.c | as | ld > foo".  (If
you want to use libraries, change that to "... | ld - -lbar > foo".)  (For
that matter, "ld" (and "cc") probably shouldn't have a shorthand notation for
libraries.  How about "LDPATH=/lib:/usr/lib:... export LDPATH"?)

This is not only conceptually simpler and cleaner, but it exploits multiple
processors without hackery.  However, in the rush to get fancy "intuitive"
user interfaces, little things like that don't get much shrift....

++Brandon
-- 
Brandon S. Allbery, moderator of comp.sources.misc	     allbery@ncoast.org
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