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From: Bart <bc@freeuk.com>
Newsgroups: comp.lang.c
Subject: Re: question about linker
Date: Fri, 29 Nov 2024 21:52:11 +0000
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On 29/11/2024 20:35, Keith Thompson wrote:
> Bart <bc@freeuk.com> writes:
> [...]
>> C's syntax allows a 14-parameter function F to be declared in the same
>> statement as a simple int 'i'.
> 
> Yes (except that it's a declaration, not a statement) :
> 
>      int i = 42, F(int, int, int, int, int, int, int,
>                    int, int, int, int, int, int, int);
> 
> Are you under the impression that anyone here was not already aware of
> that?  Would you prefer it if the number of parameters were arbitrarily
> restricted to 13?
> 
> Do you think that anyone would actually write code like the above?
> 
> C generally doesn't impose arbitrary restrictions.  Because of that,
> it's possible to write absurd code like the declaration above.  99% of
> programmers simply don't do that, so it's not a problem in practice.
> 
>> I'd say that F and i are different types! (Actually I wouldn't even
>> consider F to be type, but a function.)
> 
> Neither F nor i is a type.  i is an object (of type int), and F is a
> function (of type int(int, int, int, int, int, int, int, int, int, int,
> int, int, int, int)).
> 
>> That F(1, 2, 3.0, "5", "six", seven, ...) might yield the same type as
>> 'i' is irrelevant here.
> 
> It's relevant to the syntax.  i and F can be declared in the same
> declaration only because the type of i and the return type of F happen
> to be the same.  If F returned void, i and F would have to be declared
> separately.
> 
> Which, of course, is a good idea anyway.
> 
> You're posting repeatedly trying to convince everyone that C allows
> ridiculous code.  We already know that.  You are wasting everyone's time
> telling us something that we already know.  Most of us just don't obsess
> about it as much as you do.  Most of us recognize that, however
> convoluted C's declaration syntax might be, it cannot be fixed in a
> language calling itself "C".
> 
> Most of us here are more interested in talking about C as it's
> specified, and actually trying to understand it, than in complaining
> about it.
> 
>> Usually, given these declarations:
>>
>>    int A[100]
>>    int *B;
>>    int (*C)();
>>
>> people would consider the types of A, B and C to be array, pointer and
>> function pointer respectively. Otherwise, which of the 4 or 5 possible
>> types would you say that D has here:
>>
>>    int D[3][4][5];
>>
>> It depends on how it is used in an expression, which can be any of &D,
>> D, D[i], D[i][j], D[i][j][k], none of which include 'Array' type!
> 
> No, the object D unambiguously has type int[3][4][5]

(So it would have a different type from E declared on in the same 
declaration:

    int D[3][4][5], E;

? In that case tell that to David Brown!)


You seem have missed the point of my post, which was a reply to David's 
remark that 'they can't have totally different types' which was in 
response to my saying that each variable in the same declaration can 'be 
[of] a totally different type'.

DB is assuming the type of the variable after it's been used in an 
expression that is fully evaluated to yield its base type. So my A[100] 
is used as A[i], and D[3][4][5]  is used as D[i][j][k].

But of course they may be evaluated only partially, yielding a range of 
types.



> Would you write "const int F();"?  Or would you omit the "const"?  How
> does the fact that "const" is allowed inconvenience you?

It's another point of confusion. In my language I don't treat function 
declarations like variable declarations. A function is not a variable. 
There is no data storage associated with it.

In C it is unfortunate, as it makes it hard to trivially distinguish a 
function declaration (or the start of a function definition) from a 
variable declaration.