Is this a valid struct declaration

**rahul** · Jun 27 '08, 07:40 PM

Re: Is this a valid struct declaration

On Jun 6, 2:32 pm, Raman <ramanchalo...@ gmail.comwrote:

Hi All,
>
Is it valid:
>
struct test{
>
};
>
I mean, Can we have a struct containing no members? Is this a an
incomplete-type?
>
Please provide your expert comments.
>
Thanks,
Raman Chalotra

I don't see anything wrong with the declaration. Though this stuff
does not look like it can have any practical applications.
The standard does not mandate declaring a member in a structure. This
code compiles with '-ansi' flag on Linux/gcc.
I don't see any reason why it should not be valid.

**Ben Bacarisse** · Jun 27 '08, 07:40 PM

Re: Is this a valid struct declaration

rahul <rahulsinner@gm ail.comwrites:

On Jun 6, 2:32 pm, Raman <ramanchalo...@ gmail.comwrote:

<snip>

>struct test{
>>
>};
>>
>I mean, Can we have a struct containing no members? Is this a an
>incomplete-type?
>>
>Please provide your expert comments.
>>
>Thanks,
>Raman Chalotra

>
I don't see anything wrong with the declaration. Though this stuff
does not look like it can have any practical applications.
The standard does not mandate declaring a member in a structure.

My copy does. The syntax specifies that there must be at least one
member. Where are you getting your information from?

This
code compiles with '-ansi' flag on Linux/gcc.

Add -pedantic.

I don't see any reason why it should not be valid.

--
Ben.

**Flash Gordon** · Jun 27 '08, 07:40 PM

Re: Is this a valid struct declaration

rahul wrote:

On Jun 6, 2:32 pm, Raman <ramanchalo...@ gmail.comwrote:

>Hi All,
>>
>Is it valid:
>>
>struct test{
>>
>};
>>
>I mean, Can we have a struct containing no members?

No.

>Is this a an
>incomplete-type?

No.

>Please provide your expert comments.
>>
>Thanks,
>Raman Chalotra

>
I don't see anything wrong with the declaration.

Then you need to look at the standard more carefully:
6.7.2.1 Structure and union specifiers
Syntax
1 struct-or-union-specifier:
struct-or-union identifieropt { struct-declaration-list }
struct-or-union identifier

struct-or-union:
struct
union

struct-declaration-list:
struct-declaration
struct-declaration-list struct-declaration

Note that a struct-declaration-list ALWAYS has a struct-declaration!

Though this stuff
does not look like it can have any practical applications.
The standard does not mandate declaring a member in a structure.

Wrong. From N1256:

This
code compiles with '-ansi' flag on Linux/gcc.

That does not make it procude all required diagnostics. You need '-ansi
-pedantic' at which point it gives a warning. Note that a warning is
sufficient to meet the standards requirement for "invalid" code (a puch
in the face could also qualify, but I don't think an implementation that
did this would be very popular)

I don't see any reason why it should not be valid.

See above.

An imcomplete type would be
struct test;
--
Flash Gordon

**muks** · Jun 27 '08, 07:40 PM

Re: Is this a valid struct declaration

On Jun 6, 2:51 pm, rahul <rahulsin...@gm ail.comwrote:

On Jun 6, 2:32 pm, Raman <ramanchalo...@ gmail.comwrote:
>

Hi All,

>

Is it valid:

>

struct test{

>

};

>

I mean, Can we have a struct containing no members? Is this a an
incomplete-type?

>

Please provide your expert comments.

>

Thanks,
Raman Chalotra

>
I don't see anything wrong with the declaration. Though this stuff
does not look like it can have any practical applications.
The standard does not mandate declaring a member in a structure. This
code compiles with '-ansi' flag on Linux/gcc.
I don't see any reason why it should not be valid.

hey i dont find ne thng wrong in ur problem........ ..bt surely this
thng cannot b realised in practical situation...... rest its ok.tk cr
bye

**Jack Klein** · Jun 27 '08, 07:40 PM

Re: Is this a valid struct declaration

On Fri, 6 Jun 2008 06:45:27 -0700 (PDT), muks <mukul2cool@gma il.com>
wrote in comp.lang.c:

On Jun 6, 2:51 pm, rahul <rahulsin...@gm ail.comwrote:

On Jun 6, 2:32 pm, Raman <ramanchalo...@ gmail.comwrote:

Hi All,

Is it valid:

struct test{

};

I mean, Can we have a struct containing no members? Is this a an
incomplete-type?

Please provide your expert comments.

Thanks,
Raman Chalotra

I don't see anything wrong with the declaration. Though this stuff
does not look like it can have any practical applications.
The standard does not mandate declaring a member in a structure. This
code compiles with '-ansi' flag on Linux/gcc.
I don't see any reason why it should not be valid.

>
hey i dont find ne thng wrong in ur problem........ ..bt surely this
thng cannot b realised in practical situation...... rest its ok.tk cr
bye

hey ur a fkng mron.

--
Jack Klein
Home: http://JK-Technology.Com
FAQs for
comp.lang.c http://c-faq.com/
comp.lang.c++ http://www.parashift.com/c++-faq-lite/
alt.comp.lang.l earn.c-c++

http://www.club.cc.cmu.edu/~ajo/docs/FAQ-acllc.html

**Chris Thomasson** · Jun 27 '08, 07:40 PM

Re: Is this a valid struct declaration

"muks" <mukul2cool@gma il.comwrote in message
news:d913f2f4-92f1-4ec8-82fb-ff2f557c00c9@a3 2g2000prf.googl egroups.com...
[...]

hey i dont find ne thng wrong in ur problem........ ..bt surely this
thng cannot b realised in practical situation...... rest its ok.tk cr
bye

:^/

**Dan** · Jun 27 '08, 07:40 PM

Re: Is this a valid struct declaration

>hey i dont find ne thng wrong in ur problem........ ..bt surely this
>thng cannot b realised in practical situation...... rest its ok.tk cr
>bye

I have seen #defines that turn on and off structure members to save memory,
and one even turned all the members off.

**Ian Collins** · Jun 27 '08, 07:40 PM

Re: Is this a valid struct declaration

rahul wrote:

On Jun 6, 2:32 pm, Raman <ramanchalo...@ gmail.comwrote:

>Hi All,
>>
>Is it valid:
>>
>struct test{
>>
>};
>>
>I mean, Can we have a struct containing no members? Is this a an
>incomplete-type?
>>
>Please provide your expert comments.
>>
>Thanks,
>Raman Chalotra

>
I don't see anything wrong with the declaration. Though this stuff
does not look like it can have any practical applications.
The standard does not mandate declaring a member in a structure. This
code compiles with '-ansi' flag on Linux/gcc.
I don't see any reason why it should not be valid.

Are you sure you weren't compiling as C++?

--
Ian Collins.

**Raman** · Jun 27 '08, 07:40 PM

Re: Is this a valid struct declaration

On Jun 6, 4:56 pm, Flash Gordon <s...@flash-gordon.me.ukwro te:

rahul wrote:

On Jun 6, 2:32 pm, Raman <ramanchalo...@ gmail.comwrote:

Hi All,

>

Is it valid:

>

struct test{

>

};

>

I mean, Can we have a struct containing no members?

>
No.
>

Is this a an
incomplete-type?

>
No.
>

Please provide your expert comments.

>

Thanks,
Raman Chalotra

>

I don't see anything wrong with the declaration.

>
Then you need to look at the standard more carefully:
6.7.2.1 Structure and union specifiers
Syntax
1 struct-or-union-specifier:
struct-or-union identifieropt { struct-declaration-list }
struct-or-union identifier
>
struct-or-union:
struct
union
>
struct-declaration-list:
struct-declaration
struct-declaration-list struct-declaration
>
Note that a struct-declaration-list ALWAYS has a struct-declaration!
>

Though this stuff
does not look like it can have any practical applications.
The standard does not mandate declaring a member in a structure.

>
Wrong. From N1256:
>

This
code compiles with '-ansi' flag on Linux/gcc.

>
That does not make it procude all required diagnostics. You need '-ansi
-pedantic' at which point it gives a warning. Note that a warning is
sufficient to meet the standards requirement for "invalid" code (a puch
in the face could also qualify, but I don't think an implementation that
did this would be very popular)
>

I don't see any reason why it should not be valid.

>
See above.
>
An imcomplete type would be
struct test;
--
Flash Gordon

HI,

Yes, and
1. we cant apply sizeof to incomplete types.
2. what if we create array of this struct(incomple te), every element
having same mem address....whic h is probably violation of array
concept in itself.

Thanks,
Raman Chalotra

**Flash Gordon** · Jun 27 '08, 07:40 PM

Re: Is this a valid struct declaration

Raman wrote, On 09/06/08 10:41:

<snip>

Yes, and
1. we cant apply sizeof to incomplete types.

True.

2. what if we create array of this struct(incomple te), every element
having same mem address....whic h is probably violation of array
concept in itself.

It is an error that the compiler is required to diagnose (produce a
warning, error or tattoo the appropriate clause of the standard on some
part of your body for).
--
Flash Gordon
Inventor of strange and unusual diagnostics

Is this a valid struct declaration

Is this a valid struct declaration

Comment

Comment

Comment

Comment

Comment

Comment

Comment

Comment

Comment

Comment