Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Path: utzoo!mnetor!uunet!lll-winken!lll-lcc!pyramid!prls!gardner
From: gardner@prls.UUCP (Robert Gardner)
Newsgroups: comp.lang.c
Subject: Re: documentation standards........
Message-ID: <6917@prls.UUCP>
Date: Fri, 23-Oct-87 12:45:14 EST
Article-I.D.: prls.6917
Posted: Fri Oct 23 12:45:14 1987
Date-Received: Sun, 25-Oct-87 17:03:05 EST
References: <9897@brl-adm.ARPA>
Reply-To: gardner@prls.UUCP (Robert Gardner)
Organization: Philips Research Labs, Sunnyvale, California
Lines: 21

In article <9897@brl-adm.ARPA> tom@vax1.acs.udel.EDU (Tom Uffner) writes:
>all externals and statics can be
>initialized "for free" to nearly anything desired at compile time,
>(cf. constant expressions) but an 'initialize()' proc would generate
>code and take time to execute.

This isn't necessarily true and depends on the details of the linker
and loader (and compiler implementation). One compiler I worked with
allocates space for global variables dynamically before calling main(),
zeroes it, and then executes a bunch of initialization statements that
move the initialization values into the proper places, then calls main().
There is approx. one move for each initializer, so each initializer
takes about twice as much space as you would expect. On the other hand,
this is a net gain if there are only a few initializers compared to the
number of global variables, since allocating space for all the global
variables in the executable (as RSX does) can take more space than the
initialization code if there are a lot of globals.

I prefer compile-time initialization when possible, but it's not
necessarily "for free".

Robert Gardner