From owner-freebsd-hackers@freebsd.org  Sat Dec  9 16:52:12 2017
Return-Path: <owner-freebsd-hackers@freebsd.org>
Delivered-To: freebsd-hackers@mailman.ysv.freebsd.org
Received: from mx1.freebsd.org (mx1.freebsd.org
 [IPv6:2001:1900:2254:206a::19:1])
 by mailman.ysv.freebsd.org (Postfix) with ESMTP id 1C266E91233
 for <freebsd-hackers@mailman.ysv.freebsd.org>;
 Sat,  9 Dec 2017 16:52:12 +0000 (UTC)
 (envelope-from eric@metricspace.net)
Received: from mail.metricspace.net (mail.metricspace.net
 [IPv6:2001:470:1f11:617::107])
 by mx1.freebsd.org (Postfix) with ESMTP id E41B36C550
 for <freebsd-hackers@freebsd.org>; Sat,  9 Dec 2017 16:52:11 +0000 (UTC)
 (envelope-from eric@metricspace.net)
Received: from [IPv6:2001:470:1f11:617:3210:b3ff:fe77:ca3f] (unknown
 [IPv6:2001:470:1f11:617:3210:b3ff:fe77:ca3f])
 (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits))
 (Client did not present a certificate) (Authenticated sender: eric)
 by mail.metricspace.net (Postfix) with ESMTPSA id 4917C4FEC
 for <freebsd-hackers@freebsd.org>; Sat,  9 Dec 2017 16:52:11 +0000 (UTC)
To: "freebsd-hackers@freebsd.org" <freebsd-hackers@freebsd.org>
From: Eric McCorkle <eric@metricspace.net>
Subject: Hopefully useful: macro-controlled logger
Message-ID: <0dd5240f-6c70-425f-7e98-7946097ea3ef@metricspace.net>
Date: Sat, 9 Dec 2017 11:52:10 -0500
User-Agent: Mozilla/5.0 (X11; FreeBSD amd64; rv:52.0) Gecko/20100101
 Thunderbird/52.5.0
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Language: en-US
Content-Transfer-Encoding: 8bit
X-BeenThere: freebsd-hackers@freebsd.org
X-Mailman-Version: 2.1.25
Precedence: list
List-Id: Technical Discussions relating to FreeBSD
 <freebsd-hackers.freebsd.org>
List-Unsubscribe: <https://lists.freebsd.org/mailman/options/freebsd-hackers>, 
 <mailto:freebsd-hackers-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-hackers/>
List-Post: <mailto:freebsd-hackers@freebsd.org>
List-Help: <mailto:freebsd-hackers-request@freebsd.org?subject=help>
List-Subscribe: <https://lists.freebsd.org/mailman/listinfo/freebsd-hackers>, 
 <mailto:freebsd-hackers-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Sat, 09 Dec 2017 16:52:12 -0000

Hi folks,

At some point in the past, I recall reading about a log4j-inspired
logging API for C that used the preprocessor to avoid introducing
runtime overhead.  However, I've never been able to find this library,
so I've used my own scrappy macro collection over the years.

Anyway, on a recent flight I decided to implement a macro-controlled
logging API in earnest.

The github project can be found here: https://github.com/emc2/mcl

It provides the ability to define module-specific loggers, log at
different levels, and set a threshold for dynamically-controlled logging
levels.  Any log message more severe than the dynamic range will be
hardwired in place, and any message less severe will be removed at
compilation time.

It's not large or complicated at all, but hopefully someone will find it
useful.  If they do, I'd be more than happy to have it added to the
FreeBSD base system.