All in - pointer declaration
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I hate the question. The reason being is that the pointer is part of the type intrinsically, and I want to use it that way but C isn't always consistent about it, so it gets weird no matter what you do. Pointer syntax is funky. It just is. There's no amount of style guidelines that will defunk pointers. Ergo, I do whatever the code around me does. Usually I put it with the type but I know I'm hated for that. :laugh:
To err is human. Fortune favors the monsters.
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If pointer is part of the type, make it! Make a typedef and use that when declaring variables.
type* x, y;
- is y of a pointer type? You know that it isn't. Lots of problems have been caused by making it appear as if x and y have the same type. (Thankfully, the compiler will catch most such wrongful assumptions.) If you change it to
type y, *x;
- is now the type definition for variable x split into two parts, separated by a variable declaration? If you make a typedef, you have a clear, all-in-one-place type definition, not cluttered up by variables. And you would avoid the risk of someone assuming, in the first example, that x and y are of the same type.
I generally agree with you, but I am not all in on that agreement, if that makes sense. Here's why: You have to look up a typedef to know what it is, and typedefs everywhere make it harder to know what's going on until you can adopt the fundamental lexicon that your typedefs essentially create. That said, everything you wrote is valid. I just think there are places where it might be overkill.
To err is human. Fortune favors the monsters.
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Type* p;Robust Services Core | Software Techniques for Lemmings | Articles
The fox knows many things, but the hedgehog knows one big thing. -
I agree, but as mentioned in my post below... a thing I don't do but is very common:
const char
*a= "a",
*b= "b";tells us, in this case we are something wrong... :(
This doesn't bother me, because I never do this kind of thing.
Robust Services Core | Software Techniques for Lemmings | Articles
The fox knows many things, but the hedgehog knows one big thing. -
Have always used this style.
Type* p;
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Me too. Although since I no longer develop in C++, I use:
MyType p;
:) /ravi
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Type *p;
or
Type* p;
or even
Type * p;
Me personally, I do whatever is the current company naming conventions.
There is only one Vera Farmiga and Salma Hayek is her prophet! Advertise here – minimum three posts per day are guaranteed.
Single Step Debugger wrote:
Type* p;
As I recall it there was a column from I believe the 'C++ Users Journal' which pointed out that the following...
int i;
Is the same as
So thus a pointer should be laid out as specified in the same way. That is if one needs a rationalization for it.
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I generally agree with you, but I am not all in on that agreement, if that makes sense. Here's why: You have to look up a typedef to know what it is, and typedefs everywhere make it harder to know what's going on until you can adopt the fundamental lexicon that your typedefs essentially create. That said, everything you wrote is valid. I just think there are places where it might be overkill.
To err is human. Fortune favors the monsters.
Most programmers of *nix/C upbringing insist that #define constants are named in UPPER_CASE so that you can easily see from the name that it is a constant. Strangely enough, the majority of that very same group detests Hungarian blurb, even though the argument for the blurb is very much the same. Why isn't the conclusion identical? Well, the answer is not invented here ... I dislike both strongly. They seem fine for release 1.0. Then, as we experienced in one project, several of those static configuration parameters, #defines, were in release 2.0 made dynamically configurable, runtime modifiable. In those days we didn't have an IDE that could automatically rename a symbol throughout the project; it had to be done manually in every single file, and there were quite a few of them; it took some effort. So for quite some time, we had a number of all-uppercase variables. We experienced "Constants ain't. Variables won't." long before it became a standard rule. That project made me ask myself: Why really did I have to know at all times whether that value is constant or variable? Did it really affect my use of it? Should it? Constant-ness is sort of a "nice to know", but when it turns into a "need to know", you should stop and ask yourself: Do I really need to know? We had a very similar experience when porting code from 16 bits Windows 95 to 32 bits Windows XP, in the days when everyone spoke Hungarian. Lots of variable were expanded in size, and the renaming of them put on the todo list. Again, I asked myself (and my coworkers): Is it really significant, as seen from a problem solution point of view, whether this counter is 16 or 32 bits? Isn't it quite obvious that this other value is a string, both from is (blurbless) name and its use? Especially when moving code between different architectures, any blurb reflecting implementation (such as word length) is meaningless. For any semantics based blurb, you really don't gain much until you include, say, the struct type name in extenso - it obviously is a struct; you don't need a blurb for that! I have learned to program very much with disregard to the type definition; I don't have to look it up to see if it is a short, an int, a long or a longlong - it is large enough for its use. The float has sufficient precision for its use. If you are in doubt whether a value is a count (some sort of integer) or a measurement (some sort of float), then you should spend some time on understanding the solution at a conceptual level
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Single Step Debugger wrote:
Type* p;
As I recall it there was a column from I believe the 'C++ Users Journal' which pointed out that the following...
int i;
Is the same as
So thus a pointer should be laid out as specified in the same way. That is if one needs a rationalization for it.
Yeah, but in
int x, *y;
is the * part of the type declaration or the variable declaration? If it is part of the type declaration, then type of y is declared in two parts, with an interspersed (and rather irrelevant) variable declaration. Is that very rational? It is valid C!
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Type *p;
or
Type* p;
or even
Type * p;
Me personally, I do whatever is the current company naming conventions.
There is only one Vera Farmiga and Salma Hayek is her prophet! Advertise here – minimum three posts per day are guaranteed.
I've always preferred "
Type *p" over "Type* p". To my mind the "pointer-ness" is a property of the variable and not the type. Of course, I've also hated this:typedef Type* TypePtr. If values are declared asTypePtrand you are using pointer-dereferencing with those values, thetypedefobfuscates the original type. And before anyone pops up with "but what about...", I thinktypedef BaseType* OpaqueTypeis perfectly fine, when you're not using values ofOpaqueTypeas pointers.Software Zen:
delete this; -
I've always preferred "
Type *p" over "Type* p". To my mind the "pointer-ness" is a property of the variable and not the type. Of course, I've also hated this:typedef Type* TypePtr. If values are declared asTypePtrand you are using pointer-dereferencing with those values, thetypedefobfuscates the original type. And before anyone pops up with "but what about...", I thinktypedef BaseType* OpaqueTypeis perfectly fine, when you're not using values ofOpaqueTypeas pointers.Software Zen:
delete this;A problem with
typedef Type* TypePtr;
is that if you declare
const TypePtr p;
it is
p(the pointer itself) that isconst, notType. This can be confusing, so I avoid it.Robust Services Core | Software Techniques for Lemmings | Articles
The fox knows many things, but the hedgehog knows one big thing. -
type* (pointer is part of type) Now moving on: do you do "west const" or "east const"? Standard C++[^] (surely a lot of people - me included - don't want to do productive work today)
Mircea
constexpr static const int life_the_universe_and_everything = 42;
:-\
To err is human. Fortune favors the monsters.
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A problem with
typedef Type* TypePtr;
is that if you declare
const TypePtr p;
it is
p(the pointer itself) that isconst, notType. This can be confusing, so I avoid it.Robust Services Core | Software Techniques for Lemmings | Articles
The fox knows many things, but the hedgehog knows one big thing.Good point. To my thinking
const-ness, like pointer-ness, are properties of the variable and not the type. Part of my dislike for that sort of thing is people use some kind of naming convention (xxxPtr, xxxCPtr,...) that indicates the variant of the type. It pollutes the name space with additional identifiers you need to recognize. This replaces fundamental language syntax which is consistent by definition with arbitrary naming that may or may not be consistent. I've also noticed that thetypedefoverusers also tend to cast those types, often using language syntax, to othertypedef's they've forgotten.Software Zen:
delete this; -
constexpr static const int life_the_universe_and_everything = 42;
:-\
To err is human. Fortune favors the monsters.
Didn't expect less: west coast, shall be west const ;P
Mircea
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Type *p;
or
Type* p;
or even
Type * p;
Me personally, I do whatever is the current company naming conventions.
There is only one Vera Farmiga and Salma Hayek is her prophet! Advertise here – minimum three posts per day are guaranteed.
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Type *p;
or
Type* p;
or even
Type * p;
Me personally, I do whatever is the current company naming conventions.
There is only one Vera Farmiga and Salma Hayek is her prophet! Advertise here – minimum three posts per day are guaranteed.
I never met any convention that specifies pointer declarations so I use
Type* p;
I learnt with
Type *p;but I always found it more complex to understand: after all that identifier holds a pointer to p, so it's type is pointer. Same forType** p. Only sometimes I mix them around if there are readability reasons, for exampleType** *p;can be in my opinion more readable if p holds a pointer to a matrix (i.e. if you need to return a matrix allocated by the callee, switch the matrix to send to the callee based on something, etc).GCS/GE 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
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type *p;
Because
type* p, q
doesn't do what it looks like it does. Of course, that kicks off the argument about multiple variables per
typedeclaration.Keep Calm and Carry On
k5054 wrote:
Of course, that kicks off the argument about multiple variables per type declaration.
Not an argument: don't do that.
GCS/GE 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
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I generally agree with you, but I am not all in on that agreement, if that makes sense. Here's why: You have to look up a typedef to know what it is, and typedefs everywhere make it harder to know what's going on until you can adopt the fundamental lexicon that your typedefs essentially create. That said, everything you wrote is valid. I just think there are places where it might be overkill.
To err is human. Fortune favors the monsters.
Working with autogenerated code from both MATLAB ans AutoSAR really teaches how much
typedefanddefinecomplicate the code. Sometimes you have seven or eight redefinitions - it's Hell on Earth.GCS/GE 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
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Working with autogenerated code from both MATLAB ans AutoSAR really teaches how much
typedefanddefinecomplicate the code. Sometimes you have seven or eight redefinitions - it's Hell on Earth.GCS/GE 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
AutoSAR ? You doing automotive development ?
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AutoSAR ? You doing automotive development ?
Yep, though I'm not touching AutoSAR since a couple of years - I moved to lower level peripherals that run on TLE987x and similar.
GCS/GE 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
