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Date:      Tue, 26 Jan 2016 17:46:52 -0500 (EST)
From:      Daniel Eischen <deischen@freebsd.org>
To:        Gary Jennejohn <gljennjohn@gmail.com>
Cc:        Luigi Rizzo <rizzo@iet.unipi.it>, threads@freebsd.org, Boris Astardzhiev <boris.astardzhiev@gmail.com>, "freebsd-net@freebsd.org" <net@freebsd.org>
Subject:   Re: Does FreeBSD have sendmmsg or recvmmsg system calls?
Message-ID:  <Pine.GSO.4.64.1601261743450.12995@sea.ntplx.net>
In-Reply-To: <20160126182543.64050678@ernst.home>
References:  <20160118140811.GW3942@kib.kiev.ua> <CAP=KkTzLCOnJVqt5F3ZuuZUiwkmWcne2Ynpi6-daE2jTzSBtfw@mail.gmail.com> <20160120073154.GB3942@kib.kiev.ua> <CAP=KkTx3dAUuSBrJiwNAAe%2BhHSG4j5Qp7sAcgtOgmVi8a12k1A@mail.gmail.com> <20160121093509.GK3942@kib.kiev.ua> <20160121233040.E1864@besplex.bde.org> <CAP=KkTw=ML=oPo2OgFfmor_nsL3om6HvmTQjKNMrOiU_dmWc2g@mail.gmail.com> <20160124050634.GS3942@kib.kiev.ua> <20160124100747.551f8e3f@ernst.home> <CAP=KkTyHG9Rb%2BnrDC1TDxzjUQFca9NkVp8Suo1c_-C00RUtkuQ@mail.gmail.com> <20160126134005.GD3942@kib.kiev.ua> <CA%2BhQ2%2BivWYJMDUwzdZGW88-mWzSVfPzX212sOFVmxxN0hpZ%2BQQ@mail.gmail.com> <20160126182543.64050678@ernst.home>

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On Tue, 26 Jan 2016, Gary Jennejohn wrote:

> On Tue, 26 Jan 2016 09:06:39 -0800
> Luigi Rizzo <rizzo@iet.unipi.it> wrote:
>
>> On Tue, Jan 26, 2016 at 5:40 AM, Konstantin Belousov
>> <kostikbel@gmail.com> wrote:
>>> On Mon, Jan 25, 2016 at 11:22:13AM +0200, Boris Astardzhiev wrote:
>>>> +ssize_t
>>>> +recvmmsg(int s, struct mmsghdr *__restrict msgvec, size_t vlen, int flags,
>>>> +    const struct timespec *__restrict timeout)
>>>> +{
>>>> +     size_t i, rcvd;
>>>> +     ssize_t ret;
>>>> +
>>>> +     if (timeout != NULL) {
>>>> +             fd_set fds;
>>>> +             int res;
>>> Please move all local definitions to the beginning of the function.
>>
>> This style recommendation was from 30 years ago and is
>> bad programming practice, as it tends to complicate analysis
>> for the human and increase the chance of improper usage of
>> variables.
>>
>> We should move away from this for new code.
>>
>
> Really?  I personally find having all variables grouped together
> much easier to understand.  Stumbling across declarations in the
> middle of the code in a for-loop, for example, takes me by surprise.
>
> I also greatly dislike initializing variables in their declarations.
>
> Maybe I'm just old fashioned since I have been writing C-code for
> more than 30 years.

+1

Probably should be discouraged, but allowed on a case-by-case
basis.  One could argue that if you need to declaration blocks
in the middle of code, then that code is too complex and should
be broken out into a separate function.

-- 
DE



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