From mboxrd@z Thu Jan  1 00:00:00 1970
From: jnc@mercury.lcs.mit.edu (Noel Chiappa)
Date: Thu, 11 Sep 2014 21:54:15 -0400 (EDT)
Subject: [TUHS] Etymology of bc(1)
Message-ID: <20140912015415.DB69E18C09E@mercury.lcs.mit.edu>

    > From: Dave Horsfall <dave at horsfall.org>

    > On the *nix systems to which I have access, bc(1) is a standalone
    > program on FreeBSD and OSX, but pipes to dc(1) on OpenBSD. I cannot
    > check my Penguin box (Ubuntu)

Dude! Trying to answer questions about the origins of BC by looking at
systems this late is like trying to learn Latin by studying Italian! :-)

I looked at the Version 6 source, and it's a bunch of YACC code, but it pulls
the same technique of using a pipe to an instance of DC, viz:

	pipe(p);
	if (fork()==0) {
		close(1);
		dup(p[1]);
		close(p[0]);
		close(p[1]);
		yyinit(argc, argv);
		yyparse();
		exit();
	}
	close(0);
	dup(p[0]);
	close(p[0]);
	close(p[1]);
	execl("/bin/dc", "dc", "-", 0);

There's likely even older versions than the V6 one, but that's the earliest
source I have online on my PC for easy access.

	Noel