Date: Thu, 07 Oct 2004 21:36:13 -0600 (MDT) From: "M. Warner Losh" <imp@bsdimp.com> To: marc@msys.ch Cc: dnelson@allantgroup.com Subject: Re: syslog() reentrant when compiling with -pthread? Message-ID: <20041007.213613.34762646.imp@bsdimp.com> In-Reply-To: <A3E829CE-1820-11D9-AB94-003065F9345A@msys.ch> References: <FFEC3743-17A3-11D9-BB63-0003938168B2@msys.ch> <20041006144800.GB87201@dan.emsphone.com> <A3E829CE-1820-11D9-AB94-003065F9345A@msys.ch>
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In message: <A3E829CE-1820-11D9-AB94-003065F9345A@msys.ch>
Marc Balmer <marc@msys.ch> writes:
: Am 06.10.2004 um 16:48 schrieb Dan Nelson:
:
: > The only unsafe part is openlog(), so set that up before you start any
: > threads and you'll be okay. Once the log fd is opened, the syslog()
: > call looks to be thread-safe. Everything in there is done with local
: > variables and atomic writes.
:
: At least on OpenBSD I can use "%m" in the syslog() format string. This
: results in a call to strerror(), which is not thread safe, AFAIK. This
: probably is true for FreeBSD as well, so we have the following three
: conditions for thread safe syslog():
:
: 1) openlog() must be called before any threads that use syslog() are
: started.
: 2) The first argument to openlog() must not be NULL.
: 3) The "%m" Format String must not be used in syslog() calls.
:
: Any comments?
strerror is thread safe, unless your errno is outside of the valid
range.
Warner
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