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From: Wilco Dijkstra <Wilco.Dijkstra@arm.com>
To: Paul Eggert <eggert@cs.ucla.edu>,
	Adhemerval Zanella Netto <adhemerval.zanella@linaro.org>,
	Alejandro Colomar <alx.manpages@gmail.com>,
	"linux-man@vger.kernel.org" <linux-man@vger.kernel.org>
Cc: Alejandro Colomar <alx@kernel.org>,
	"libc-alpha@sourceware.org" <libc-alpha@sourceware.org>,
	"G. Branden Robinson" <g.branden.robinson@gmail.com>
Subject: Re: [PATCH] bind.2, mount_setattr.2, openat2.2, perf_event_open.2, pidfd_send_signal.2, recvmmsg.2, seccomp_unotify.2, select_tut.2, sendmmsg.2, set_thread_area.2, sysctl.2, bzero.3, getaddrinfo.3, getaddrinfo_a.3, getutent.3, mbrtowc.3, mbsinit.3, rti...
Date: Thu, 5 Jan 2023 21:12:16 +0000	[thread overview]
Message-ID: <PAWPR08MB8982513ADD350AC12E758ED483FA9@PAWPR08MB8982.eurprd08.prod.outlook.com> (raw)
In-Reply-To: <18377873-00df-84fa-a9e9-5d1207e4ea52@cs.ucla.edu>

Hi,

>> bzero is deprecated by POSIX.1-2001, removed by POSIX.1-2008, and on glibc
>> implementation now calls memset (previously some architecture added ifunc
>> redirection to optimized bzero to avoid the extra function call, it was
>> removed from all architectures).
>> 
>> Also, GCC for some time also replaces bzero with memset so there is no gain
>> in actually call bzero (check glibc commit 9403b71ae97e3f1a91c796ddcbb4e6f044434734).

Agreed, there is no benefit from using it, and certainly no reason to try to undo
its removal. We should promote standards, not try to subvert them...
A more productive way would be to propose new functions to the C/C++
committees.

> In addition, gcc -Wall warns if you mistakenly pass 0 as memset's 3rd 
> arg, which undercuts the argument that bzero avoids silly mistakes.

Also I think GCC should give a deprecated/obsolete warning (or perhaps error?)
when using bzero, bcmp, bcopy, index, rindex etc so people can start removing
the few remaining uses from ancient code.

Cheers,
Wilco

  reply	other threads:[~2023-01-05 21:12 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-01-05 19:37 [PATCH] bind.2, mount_setattr.2, openat2.2, perf_event_open.2, pidfd_send_signal.2, recvmmsg.2, seccomp_unotify.2, select_tut.2, sendmmsg.2, set_thread_area.2, sysctl.2, bzero.3, getaddrinfo.3, getaddrinfo_a.3, getutent.3, mbrtowc.3, mbsinit.3, rtime.3, rtnetlink.3, strptime.3, NULL.3const, size_t.3type, void.3type, aio.7, netlink.7, unix.7: Prefer bzero(3) over memset(3) Alejandro Colomar
2023-01-05 20:48 ` Adhemerval Zanella Netto
2023-01-05 20:55   ` Paul Eggert
2023-01-05 21:12     ` Wilco Dijkstra [this message]
2023-01-05 21:33       ` [PATCH] bind.2, mount_setattr.2, openat2.2, perf_event_open.2, pidfd_send_signal.2, recvmmsg.2, seccomp_unotify.2, select_tut.2, sendmmsg.2, set_thread_area.2, sysctl.2, bzero.3, getaddrinfo.3, getaddrinfo_a.3, getutent.3, mbrtowc.3, mbsinit.3, rti Alejandro Colomar
2023-01-05 23:30       ` Wilco Dijkstra
2023-01-05 21:42     ` [PATCH] bind.2, mount_setattr.2, openat2.2, perf_event_open.2, pidfd_send_signal.2, recvmmsg.2, seccomp_unotify.2, select_tut.2, sendmmsg.2, set_thread_area.2, sysctl.2, bzero.3, getaddrinfo.3, getaddrinfo_a.3, getutent.3, mbrtowc.3, mbsinit.3, rtime.3, rtnetlink.3, strptime.3, NULL.3const, size_t.3type, void.3type, aio.7, netlink.7, unix.7: Prefer bzero(3) over memset(3) Alejandro Colomar
2023-01-06 10:55   ` Christian Brauner
2023-01-06  0:02 [PATCH] bind.2, mount_setattr.2, openat2.2, perf_event_open.2, pidfd_send_signal.2, recvmmsg.2, seccomp_unotify.2, select_tut.2, sendmmsg.2, set_thread_area.2, sysctl.2, bzero.3, getaddrinfo.3, getaddrinfo_a.3, getutent.3, mbrtowc.3, mbsinit.3, rti Wilco Dijkstra
2023-01-06  0:22 ` Alejandro Colomar
2023-01-06  0:57   ` Alejandro Colomar
2023-01-06  2:26 Wilco Dijkstra
2023-01-06 13:49 ` Alejandro Colomar
2023-01-06 15:53 Wilco Dijkstra
2023-01-06 16:20 ` Alejandro Colomar
2023-01-06 17:01   ` Joseph Myers

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