Date: Wed, 20 Jan 2016 09:31:55 +0200 From: Konstantin Belousov <kostikbel@gmail.com> To: Boris Astardzhiev <boris.astardzhiev@gmail.com> Cc: Jilles Tjoelker <jilles@stack.nl>, net@freebsd.org, threads@freebsd.org Subject: Re: Does FreeBSD have sendmmsg or recvmmsg system calls? Message-ID: <20160120073154.GB3942@kib.kiev.ua> In-Reply-To: <CAP=KkTzLCOnJVqt5F3ZuuZUiwkmWcne2Ynpi6-daE2jTzSBtfw@mail.gmail.com> References: <CAP=KkTwG0SVUmrBuWm33EC-tG4tMTdF5rLZQ_u6G1=-ujnfjkA@mail.gmail.com> <20160113080349.GC72455@kib.kiev.ua> <CAP=KkTxVaqZvigg78Dg%2Bv8kuTCaZyky8x15NHqD9uabuRKRkMw@mail.gmail.com> <20160116195657.GJ3942@kib.kiev.ua> <20160116202534.GK3942@kib.kiev.ua> <20160117211853.GA37847@stack.nl> <20160118044826.GS3942@kib.kiev.ua> <CAP=KkTy3J=k7hokGhohcGXv%2BWLnaxJmiAPxqmX9FHt7k0=Dp7Q@mail.gmail.com> <20160118140811.GW3942@kib.kiev.ua> <CAP=KkTzLCOnJVqt5F3ZuuZUiwkmWcne2Ynpi6-daE2jTzSBtfw@mail.gmail.com>
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On Tue, Jan 19, 2016 at 01:58:27PM +0200, Boris Astardzhiev wrote:
> +int
> +recvmmsg(int s, struct mmsghdr *msgvec, unsigned int vlen, int flags)
> +{
> + int i, ret, rcvd;
Shouldn't i and rcvd be unsigned as well ? Shouldn't return value
also be unsigned ?
> +
> + if (vlen > VLEN_MAX)
> + vlen = VLEN_MAX;
Why is this restriction needed ?
> +
> + rcvd = 0;
> + for (i = 0; i < vlen; i++) {
> + errno = 0;
> + ret = __sys_recvmsg(s, &msgvec[i].msg_hdr, flags);
> + if (ret < 0 || errno != 0) {
I do not see why do you need to clear errno before, and then do this test.
Just check ret == -1, in which case errno was set from the immediate syscall.
> + if (rcvd != 0) {
> + /* We've received messages. Let caller know. */
> + errno = 0;
This cleaning is not needed as well. For successfull functions returns,
errno value is undefined.
> + return (rcvd);
> + }
> + return (-1);
> + }
> +
> + /* Save received bytes */
> + msgvec[i].msg_len = ret;
> +
Extra empty line.
> + rcvd++;
> + }
> +
> + return (rcvd);
> +}
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