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Re: I heard this somewhere

Peter_in_27809-Jul-21 16:12

Peter_in_2780

9-Jul-21 16:12

You're probably referring to this thread[^]. I only remember it because I made a flippant comment.

Software rusts. Simon Stephenson, ca 1994. So does this signature. me, 2012

Re: I heard this somewhere

Randor 9-Jul-21 17:20

Randor

9-Jul-21 17:20

Richard Andrew x64 wrote:
Can anyone explain the theory behind this?

Hi,

I can give you an example of why using-declarations should be avoided.

Sometime ago I was on a two-man team (Hello Andy !) working on the Delivery Optimization system service[^] which would debut with Windows 10 Threshold. The original code base was developed with VS2010 and 'using namespace boost' was sprinkled throughout much of our source code.

The first problem we encountered was that boost::chrono, boost::atomic, and boost:mutex conflicted with std::chrono, std::atmomic and std:mutex. There were a few other issues with std::thread but I can't remember them all. We spent several days (probably a week) refactoring our code.

When C++17 came around I had a similar problem with boost::filesystem conflicting with std::filesystem in other projects.

We eventually moved away from boost to the std namespace when the internal OS build system added support for C++11. Now days I just type the entire scope and avoid using-declarations.

Re: I heard this somewhere

Richard Andrew x649-Jul-21 17:41

Richard Andrew x64

9-Jul-21 17:41

Very interesting. I think I haven't worked on anything in C++ that's sufficiently complex to have had such a problem. Smile | :)

But I thank you for taking the time to explain it.

The difficult we do right away...
...the impossible takes slightly longer.

Re: I heard this somewhere

Randor 9-Jul-21 18:32

Randor

9-Jul-21 18:32

Yeah,

Shortly after I responded to your post I remembered some other details. I can remember that std::mutex and boost::mutex were nearly identical so I could seamlessly switch the code below from boost to the std namespace simply by changing the using-namespace declaration. It's a bit frightening when you discover three days later that you forgot to change a mutex in a few places.

C++

//using namespace boost;
//using namespace std;

mutex m;
m.lock();
//... something here
m.unlock();

Can't make that mistake if you use the entire scope:

C++

std::mutex m;
m.lock();
//... something here
m.unlock();

Re: I heard this somewhere

Nelek10-Jul-21 6:10

Nelek

10-Jul-21 6:10

Randor wrote:
Can't make that mistake if you use the entire scope:

care to elaborate?

M.D.V.

If something has a solution... Why do we have to worry about?. If it has no solution... For what reason do we have to worry about?
Help me to understand what I'm saying, and I'll explain it better to you
Rating helpful answers is nice, but saying thanks can be even nicer.

Re: I heard this somewhere

Randor 10-Jul-21 6:44

Randor

10-Jul-21 6:44

Nelek wrote:
care to elaborate?

We are discussing C++ namespaces[^]. C++ code containing using-declarations[^] can lead to scope resolution ambiguity.

boost::mutex[^]
std::mutex[^]

I am sharing my opinion that using-declarations should be avoided.

Best Wishes,
-David Delaune

Re: I heard this somewhere

Nelek10-Jul-21 14:58

Nelek

10-Jul-21 14:58

Yeah, I had understood so far.

But I didn't get the sentence I quoted.

I suppose that you meant using the "std::" or "boost::" as prefix, you have less probability of getting errors than unsing both "using", i.e. because some methods might have similar parameters but different behaviour.

M.D.V.

Re: I heard this somewhere

honey the codewitch9-Jul-21 18:21

honey the codewitch

9-Jul-21 18:21

Personally, I think it's fine in your main.cpp

Anywhere else, such as in a header, it clutters your global naming container.

In general, don't use "using namespace" in headers at all.

Some people here might suggest that using namespace std, even in main.cpp is bad form because of all the stuff it drags in.

I suggest those people relax. Smile | :)

Real programmers use butterflies

Re: I heard this somewhere

den2k8811-Jul-21 21:17

den2k88

11-Jul-21 21:17

honey the codewitch wrote:
Some people here might suggest that using namespace std, even in main.cpp is bad form because of all the stuff it drags in.

As if linkers are that stupid...

GCS d--(d-) s-/++ a C++++ U+++ P- L+@ E-- W++ N+ o+ K- w+++ O? M-- V? PS+ PE- Y+ PGP t+ 5? X R+++ tv-- b+(+++) DI+++ D++ G e++ h--- r+++ y+++* Weapons extension: ma- k++ F+2 X

Re: I heard this somewhere

honey the codewitch12-Jul-21 0:49

honey the codewitch

12-Jul-21 0:49

Not that. Just that people don't like intellisense coming up with a billion and a half entries every time it opens.

Real programmers use butterflies

Re: I heard this somewhere

den2k8812-Jul-21 1:22

den2k88

12-Jul-21 1:22

I use VisualAssistX, it usually gives good entries anyway.

GCS d--(d-) s-/++ a C++++ U+++ P- L+@ E-- W++ N+ o+ K- w+++ O? M-- V? PS+ PE- Y+ PGP t+ 5? X R+++ tv-- b+(+++) DI+++ D++ G e++ h--- r+++ y+++* Weapons extension: ma- k++ F+2 X

Re: I heard this somewhere

honey the codewitch12-Jul-21 1:31

honey the codewitch

12-Jul-21 1:31

I just use VS Code with minimal frills when I do C++. It mostly stays out of my way and that's what I like about it. It has a few quirks, but so does everything.

Real programmers use butterflies

Re: I heard this somewhere

den2k8812-Jul-21 1:37

den2k88

12-Jul-21 1:37

I tried VSCode and while I find it all in all good I despise its side-panels management. When I can I cram everything in VS and use the external toolchain to compile. I'm using it for an embedded Linux sw, I used it for microcontrollers... Big Grin | :-D

GCS d--(d-) s-/++ a C++++ U+++ P- L+@ E-- W++ N+ o+ K- w+++ O? M-- V? PS+ PE- Y+ PGP t+ 5? X R+++ tv-- b+(+++) DI+++ D++ G e++ h--- r+++ y+++* Weapons extension: ma- k++ F+2 X

Re: I heard this somewhere

honey the codewitch12-Jul-21 1:58

honey the codewitch

12-Jul-21 1:58

They never bothered me that much. Once I got the hang of ctrl+click to open in the side it was all gravy for me.

Mostly I like VS Code because it's got a nice mix of minimal UI wrapped around maximum functionality. I have yet to find a file type it can't open. Makes it super nice for me working on my TTF library because I can just open a test font file and look at all the glyphs in VS Code.

I really hope they backport some of that functionality into Visual Studio or something but I doubt it because they are such different products.

Real programmers use butterflies

Re: I heard this somewhere

KateAshman12-Jul-21 3:50

KateAshman

12-Jul-21 3:50

A.k.a. namespace pollution.

If you import a large amount of classes/functions, that you do not know the name of, you end up with a higher risk of running into namespace collisions.

Message Closed

9-Jul-21 10:19

User 15245513

9-Jul-21 10:19

Message Closed

modified 6-Aug-21 21:01pm.

Re: You are a rock ... this for the weekend

User 152455139-Jul-21 11:08

User 15245513

9-Jul-21 11:08

Old furt's song
ZZ Top - La Grange (Live From Gruene Hall) - YouTube[^]

modified 6-Aug-21 21:01pm.

Re: You are a rock ... this for the weekend

User 152455139-Jul-21 11:08

User 15245513

9-Jul-21 11:08

No technis, no cheat, simply _the_ voice................
Elvis Presley - My Way (Aloha From Hawaii, Live in Honolulu, 1973) - YouTube[^]

modified 6-Aug-21 21:01pm.

You are a number

Gerry Schmitz9-Jul-21 6:08

Gerry Schmitz

9-Jul-21 6:08

Anyone who has played "shooter" games knows about "hit points".

I was fascinated to find rules for an 1824 Prussian war game that was attributed to later Prussian military successes. Back then they were assigning hit points to units.

As infantry in 3 ranks: .2 HP per man
In 2 ranks: .33 HP
Skirmishers: .66 HP
etc.

A half-Battalion (450 men) can "fire" anywhere from 2 - 60 HP, depending on range and probabilities.

I want to be a skirmisher.

It was only in wine that he laid down no limit for himself, but he did not allow himself to be confused by it.
― Confucian Analects: Rules of Confucius about his food

I am not a number.

OriginalGriff9-Jul-21 6:29

OriginalGriff

9-Jul-21 6:29

I am a free man![^]

"I have no idea what I did, but I'm taking full credit for it." - ThisOldTony
"Common sense is so rare these days, it should be classified as a super power" - Random T-shirt
AntiTwitter: @DalekDave is now a follower!

Re: I am not a number.

kmoorevs9-Jul-21 7:57

kmoorevs

9-Jul-21 7:57

Aw man! Don't leave me hanging! A great intro to a great song! Laugh | :laugh:

Up the irons!!! Cool | :cool:

Iron Maiden- The Prisoner - YouTube[^]

"Go forth into the source" - Neal Morse
"Hope is contagious"

Re: I am not a number.

jeron19-Jul-21 8:05

jeron1

9-Jul-21 8:05

Great song. Thumbs Up | :thumbsup:

"the debugger doesn't tell me anything because this code compiles just fine" - random QA comment
"Facebook is where you tell lies to your friends. Twitter is where you tell the truth to strangers." - chriselst
"I don't drink any more... then again, I don't drink any less." - Mike Mullikins uncle

Re: I am not a number.

den2k8811-Jul-21 21:20

den2k88

11-Jul-21 21:20

CP is missing the "horns" emoji. I'll use Beer | [beer]

, wich is a good synonim*

* I dislike beer and am always in a embarassing position with my fellow metalheads. If only cider was common here in Italy.

GCS d--(d-) s-/++ a C++++ U+++ P- L+@ E-- W++ N+ o+ K- w+++ O? M-- V? PS+ PE- Y+ PGP t+ 5? X R+++ tv-- b+(+++) DI+++ D++ G e++ h--- r+++ y+++* Weapons extension: ma- k++ F+2 X

Re: I am not a number.

Maximilien9-Jul-21 8:02

Maximilien

9-Jul-21 8:02

One of the great TV series.

I don't know if it could be possible to remake it in these modern times.

CI/CD = Continuous Impediment/Continuous Despair

Re: I am not a number.

obermd9-Jul-21 10:06

obermd

9-Jul-21 10:06

So did you ever figure out who Number 1 is? It's in the very last episode of the series.

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