[Interest] Interest Digest, Vol 79, Issue 19
Roland Hughes
roland at logikalsolutions.com
Wed Apr 25 15:53:26 CEST 2018
On 04/25/2018 08:24 AM, Thiago Macieira wrote:
> Another issue is that QDataStream tries to store all integers in big endian,
> unless you tell it otherwise. Since most machines are little-endian, that's a
> waste of CPU cycles, as you're doing the endian conversion twice, for little
> gain, however fast it is.
Be gentle and tread lightly here. Don't just take an x86 view of the
world when considering this change. Having gray in the hair and a long
time in the field has me recalling a reason behind that. Many embedded
Qt projects were creating devices which fed data via hook or crook back
to IBM, Amdahl, Prime, PowerPC based, etc. While Amdahl and Prime have
ceased production they are still in the field and still being fed.
https://www.indeed.com/viewjob?jk=f0ccbd43e9217ed2&q=amdahl&tk=1cbugjg1f1a4o2lk&from=web&vjs=3
Unisys was little-endian but the COBOL compiler had USAGE IS COMP
clauses which would import/use big-endian format. One of the few which
had that. Most everyone else had to use FORTRAN or role their own
special COBOL libraries. Yes, most of the systems catching the output
were COBOL. It still is the largest "production" language in the world
by application size and base.
What I'm trying to tell you is there was and still is a legitimate
reason to have a QDataStream which can write big-endian. Don't just rip
it out. Make it some kind of settable boolean flag in the class. There
is no way to know just how many of these things are still out there and
are still being developed. Most were in the world of defense
contractor/military
--
Roland Hughes, President
Logikal Solutions
(630)-205-1593
http://www.theminimumyouneedtoknow.com
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