mailing list mirror (one of many)
 help / color / mirror / code / Atom feed
From: Jeff King <>
To: Johannes Schindelin <>
Cc: Junio C Hamano <>,
	Johannes Schindelin via GitGitGadget <>,
Subject: Re: [PATCH 1/2] pkt-line: fix declaration of `set_packet_header()`
Date: Tue, 14 May 2019 10:44:39 -0400	[thread overview]
Message-ID: <> (raw)
In-Reply-To: <>

On Tue, May 14, 2019 at 10:43:06AM -0400, Jeff King wrote:

> On Tue, May 14, 2019 at 02:57:01PM +0200, Johannes Schindelin wrote:
> > > But the parameter treated as a constant without getting modified
> > > during the invocation of the function is an implementation detail of
> > > the function; there is no point exposing that implementation detail
> > > to its callers.  It does not even help the compilers handling the
> > > caller's compilation unit---the parameter is passed by value, so the
> > > caller knows that the callee would not modify it without "const"
> > > there.
> > >
> > > Does the language even allow flagging "const int in the definition,
> > > int in the declaration" as a warning-worthy discrepancy?
> > 
> > Apparently it does, as MS Visual C does issue a warning (and with `/Wall`,
> > it fails).
> > 
> > In any case, I don't think that it makes sense to have a function
> > declaration whose signature differs from the definition's.
> I actually agree with Junio's point that in an ideal world the
> declaration should omit details that are not relevant to the caller. But
> clearly we do not live in that world, and this is a small enough point
> that we should fix it in one direction or the other.
> I do have a slight preference for going the _other_ way. There is no
> need to mark the parameter as const in the definition. It is passed by
> value, so nobody except the function body cares either way. And we have
> many function bodies where value-passed parameters (or local variables!)
> are not marked as const, even though they are only assigned to once.
> I don't think that annotation is telling much to any reader of the code,
> nor to a decent optimizing compiler.

To be clear, I can live with your patch as-is, and I don't think this
one site overly matters. Mostly I do not want to see "let's declare
pass-by-value parameters as const" picked up as a general concept, and
it seems easiest to try to squash the first instance of it.  :)


  reply	other threads:[~2019-05-14 14:44 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-05-13 22:43 [PATCH 0/2] pkt-line: fix incorrect function declaration Johannes Schindelin via GitGitGadget
2019-05-13 22:43 ` [PATCH 1/2] pkt-line: fix declaration of `set_packet_header()` Johannes Schindelin via GitGitGadget
2019-05-13 23:24   ` Junio C Hamano
2019-05-14 12:57     ` Johannes Schindelin
2019-05-14 14:43       ` Jeff King
2019-05-14 14:44         ` Jeff King [this message]
2019-05-15  1:42         ` Junio C Hamano
2019-05-15  1:44           ` Jeff King
2019-05-15 10:39           ` Johannes Schindelin
2019-05-16  2:24             ` Junio C Hamano
2019-05-16  3:42               ` Jeff King
2019-05-16  4:28                 ` Junio C Hamano
2019-05-17 18:54               ` Johannes Schindelin
2019-05-13 22:43 ` [PATCH 2/2] parse-options: adjust `parse_opt_unknown_cb()`s declared return type Johannes Schindelin via GitGitGadget
2019-05-13 23:29   ` Junio C Hamano

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:

  List information:

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \ \ \ \ \ \ \

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
Code repositories for project(s) associated with this public inbox

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).