Date: Fri, 15 Nov 1996 14:37:11 -0600 (CST) From: Joe Greco <jgreco@brasil.moneng.mei.com> To: fenner@parc.xerox.com (Bill Fenner) Cc: terry@lambert.org, jdp@polstra.com, scrappy@ki.net, jgreco@brasil.moneng.mei.com, hackers@freebsd.org Subject: Re: Sockets question... Message-ID: <199611152037.OAA28878@brasil.moneng.mei.com> In-Reply-To: <96Nov15.112419pst.177557@crevenia.parc.xerox.com> from "Bill Fenner" at Nov 15, 96 11:24:14 am
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> In message <199611151706.KAA26239@phaeton.artisoft.com> Terry wrote:
> >How do I read into a structure on a machine that demands aligned
> >data access?
>
> You read into an intermediate buffer and copy it. You have to convert from
> network to machine representation anyway, so this isn't (much) more overhead.
> Or you use UDP if you want a record-oriented protocol.
Actually... I usually found it easier to do the following.
#include <stdio.h>
/*
* One dull variant of Joe's "xread" function.
*/
int xread(fd, buf, siz)
int fd;
char *buf;
int siz;
{
int rval;
int chrs = 0;
while (siz) {
if ((rval = read(fd, buf, siz)) < 0) {
return(rval);
}
chrs += rval;
siz -= rval;
buf += rval;
}
}
int main()
{
int rval;
struct big_ugly {
yadda;
yadda;
yadda;
} data;
if ((rval = xread(fd, (char *)&data, sizeof(data))) != sizeof(data)) {
fprintf(stderr, "Help me, I am on fire, xread returned %d\n",
rval);
}
}
This of course assumes you either do not need to do byte reordering, or do
it elsewhere.
... JG
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