"void Method()" vs "void Method(void)"

[Ollej Reemt]

Hello,

I would like to know if there is a difference in c++ between the
following two method-declarations:

void Method();

and

void Method(void);
I know there is a difference in C (the first case means the function may
have parameters, but they are not yet defined?).
But how is the semantik in C++? Is there a difference or are both
declarations equal in _every_ case?

I would be glad to get an answer to this question (and perhaps a
reference where this topic is explained (C++-standard?)).

Regards
ollej

[Sharad Kala]

"Ollej Reemt" <ol***@gmx.de> wrote in message
news:d4********@news.Informatik.Uni-Oldenburg.DE...

Hello,

I would like to know if there is a difference in c++ between the
following two method-declarations:

void Method();

and

void Method(void);

They are same. Former is the preferred type in C++. Reference to the
Standard --

8.3.5/2 - "...If the parameter-declaration-clause is empty, the function
takes no arguments. The parameter list (void) is equivalent to the empty
parameter list."

Sharad

[Thomas Matthews]

Ollej Reemt wrote:

Hello,

I would like to know if there is a difference in c++ between the
following two method-declarations:

void Method();

and

void Method(void);
I know there is a difference in C (the first case means the function may
have parameters, but they are not yet defined?).
But how is the semantik in C++? Is there a difference or are both
declarations equal in _every_ case?

I would be glad to get an answer to this question (and perhaps a
reference where this topic is explained (C++-standard?)).

Regards
ollej

In addition to Sharad's reply, I prefer the latter method since
it is explicit and works in both languages.

--
Thomas Matthews

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[Oliver Robbe]

Hello Sharad and Thomas,

thanks for your answers, that was exactly what I wanted to know.

Regards
ollej

[Rolf Magnus]

Thomas Matthews wrote:

I know there is a difference in C (the first case means the function may
have parameters, but they are not yet defined?).
But how is the semantik in C++? Is there a difference or are both
declarations equal in _every_ case?

I would be glad to get an answer to this question (and perhaps a
reference where this topic is explained (C++-standard?)).

Regards
ollej

In addition to Sharad's reply, I prefer the latter method since
it is explicit and works in both languages.

The point about it working in both languages is valid - if you make a header
that is supposed to be used in both languages, but how is it explicit?
IMHO, if you want to say "no parameters", the most explicit way to describe
that is by putting no parameters between the parens, not by putting a fake
parameter of type void there.

[Kristo]

Rolf Magnus wrote:

Thomas Matthews wrote:

I know there is a difference in C (the first case means the
function may have parameters, but they are not yet defined?).
But how is the semantik in C++? Is there a difference or are both
declarations equal in _every_ case?

I would be glad to get an answer to this question (and perhaps a
reference where this topic is explained (C++-standard?)).

Regards
ollej

In addition to Sharad's reply, I prefer the latter method since
it is explicit and works in both languages.

The point about it working in both languages is valid - if you make a
header that is supposed to be used in both languages, but how is it
explicit? IMHO, if you want to say "no parameters", the most explicit
way to describe that is by putting no parameters between the parens,
not by putting a fake parameter of type void there.

I believe 'explicit' in this case refers to what Ollej originally said:
in C, an empty parameter list does not necessarily mean that the
function takes no arguments. In a header file shared between C and C++
code, foo(void) will *explicitly* tell either language that foo takes
no arguments. Writing foo() will only explicitly say that to C++ code.

Kristo

[Victor Bazarov]

Kristo wrote:

Rolf Magnus wrote:

Thomas Matthews wrote:

I know there is a difference in C (the first case means the
function may have parameters, but they are not yet defined?).
But how is the semantik in C++? Is there a difference or are both
declarations equal in _every_ case?

I would be glad to get an answer to this question (and perhaps a
reference where this topic is explained (C++-standard?)).

Regards
ollej

In addition to Sharad's reply, I prefer the latter method since
it is explicit and works in both languages.

The point about it working in both languages is valid - if you make a
header that is supposed to be used in both languages, but how is it
explicit? IMHO, if you want to say "no parameters", the most explicit
way to describe that is by putting no parameters between the parens,
not by putting a fake parameter of type void there.

I believe 'explicit' in this case refers to what Ollej originally said:
in C, an empty parameter list does not necessarily mean that the
function takes no arguments. In a header file shared between C and C++
code, foo(void) will *explicitly* tell either language that foo takes
no arguments. Writing foo() will only explicitly say that to C++ code.

And what Rolf said is still true: in English having something to designate
nothing is the source of confusion. Haven't you seen (in the Standard, no
less) pages, where the only _content_ is "this page is left intentionally
blank". Isn't it a self-contradictory statement? That's what "explicitly
emtpy argument list" means in C++: no arguments, nothing between the
opening parenthesis and the closing one. I actually strongly agree with
Rolf on this one. To be _explicit_, one should simply have bare parens.

V

[Jack Klein]

On Wed, 20 Apr 2005 14:43:57 -0400, Victor Bazarov
<v.********@comAcast.net> wrote in comp.lang.c++:

Kristo wrote:

Rolf Magnus wrote:

Thomas Matthews wrote:
>I know there is a difference in C (the first case means the
>function may have parameters, but they are not yet defined?).
>But how is the semantik in C++? Is there a difference or are both
>declarations equal in _every_ case?
>
>I would be glad to get an answer to this question (and perhaps a
>reference where this topic is explained (C++-standard?)).
>
>Regards
>ollej

In addition to Sharad's reply, I prefer the latter method since
it is explicit and works in both languages.

The point about it working in both languages is valid - if you make a
header that is supposed to be used in both languages, but how is it
explicit? IMHO, if you want to say "no parameters", the most explicit
way to describe that is by putting no parameters between the parens,
not by putting a fake parameter of type void there.

I believe 'explicit' in this case refers to what Ollej originally said:
in C, an empty parameter list does not necessarily mean that the
function takes no arguments. In a header file shared between C and C++
code, foo(void) will *explicitly* tell either language that foo takes
no arguments. Writing foo() will only explicitly say that to C++ code.

And what Rolf said is still true: in English having something to designate
nothing is the source of confusion. Haven't you seen (in the Standard, no
less) pages, where the only _content_ is "this page is left intentionally
blank". Isn't it a self-contradictory statement? That's what "explicitly
emtpy argument list" means in C++: no arguments, nothing between the
opening parenthesis and the closing one. I actually strongly agree with
Rolf on this one. To be _explicit_, one should simply have bare parens.

V

Once upon a time, I wrote the users manual for a product. I generated
some of the illustrations from AutoCAD drawings of some of the
mechanical parts. As a joke, I created one drawing of a part cracked
in half to go along with the text warning the user about doing
something that could cause damage.

The powers that be saw it, decided it was funny, and wanted it in the
manual. Then at the very last minute, they changed their mind and
wanted it out.

So when the manual was printed, it had several of those pages that
said "this page intentionally blank", and one page, the one that had
held that particular illustration, that said "this page
unintentionally left blank."

Nobody ever noticed.

--
Jack Klein
Home: http://JK-Technology.Com
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