The following declaration is valid:
struct {int x;};
There's no tag and no variable.
Does it has any use?
Thanks.
Joey.
struct {int x;};
There's no tag and no variable.
Does it has any use?
Thanks.
Joey.
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Re: Struct declaration with no tag and no init-declarator-list
Hi
On Thu, 12 Jun 2008 08:19:58 -0700, JoseMariaSola wrote:
On it's own, it does nothing. Inside another struct or union, itsstruct {int x;};
>
There's no tag and no variable.
>
Does it has any use?
member(s) can be accessed as if they were members of the parent. eg:
struct {
struct {int x;};
}
foo;
foo. x= 7;
which is easier than:
struct {
struct {int x;} bar;
}
foo;
foo. bar. x= 7;
HTH
viza
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Re: Struct declaration with no tag and no init-declarator-list
On Thu, 12 Jun 2008 15:25:36 +0000, viza wrote:
PS: I didn't realise that that's non-standard. Flames may follow...>>struct {int x;};
On it's own, it does nothing. Inside another struct or union, its
member(s) can be accessed as if they were members of the parent. eg:
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Re: Struct declaration with no tag and no init-declarator-list
On Thu, 12 Jun 2008 08:19:58 -0700, JoseMariaSola wrote:No, it isn't. It's not a syntax error, but C requires a declaration toThe following declaration is valid:
>
struct {int x;};
actually declare something.
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Re: Struct declaration with no tag and no init-declarator-list
viza <tom.viza@gmil. comwrites:No, you can't, at least not in standard C. Some compilers may offerOn Thu, 12 Jun 2008 08:19:58 -0700, JoseMariaSola wrote:
>>>struct {int x;};
>>
>There's no tag and no variable.
>>
>Does it has any use?
On it's own, it does nothing. Inside another struct or union, its
member(s) can be accessed as if they were members of the parent. eg:
>
struct {
struct {int x;};
}
foo;
>
foo. x= 7;
>
which is easier than:
>
struct {
struct {int x;} bar;
}
foo;
>
foo. bar. x= 7;
it as an extension. But if you want your code to be portable, you'll
just have to write "foo.bar.x" (or do some ugly macro stuff).
--
Keith Thompson (The_Other_Keit h) kst-u@mib.org <http://www.ghoti.net/~kst>
Nokia
"We must do something. This is something. Therefore, we must do this."
-- Antony Jay and Jonathan Lynn, "Yes Minister"
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Re: Struct declaration with no tag and no init-declarator-list
The following declaration is valid:Is it a static semantic error? My compiler doesn't detect it. Is it>>struct {int x;};
No, it isn't. It's not a syntax error, but C requires a declaration to
actually declare something.
broken?
In the Standard I didn't find any restriction.
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Re: Struct declaration with no tag and no init-declarator-list
On Thu, 12 Jun 2008 09:13:27 -0700, JoseMariaSola wrote:It's a constraint violation, which requires a diagnostic from any>>>The following declaration is valid:>>struct {int x;};
>No, it isn't. It's not a syntax error, but C requires a declaration to
>actually declare something.
Is it a static semantic error?
conforming implementation.
If you asked it to try to conform to the standard, then yes.My compiler doesn't detect it. Is it
broken?
It's in 6.7p2: "A declaration shall declare at least a declarator (otherIn the Standard I didn't find any restriction.
than the parameters of a function or the members of a structure or union),
a tag, or the members of an enumeration." Your declaration does not
declare any of those.
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Re: Struct declaration with no tag and no init-declarator-list
On Jun 12, 1:16 pm, Harald van D©¦k <true...@gmail. comwrote:Thanks!On Thu, 12 Jun 2008 09:13:27 -0700, JoseMariaSola wrote:>The following declaration is valid:>struct {int x;};>No, it isn't. It's not a syntax error, but C requires a declaration to
actually declare something.>Is it a static semantic error?
It's a constraint violation, which requires a diagnostic from any
conforming implementation.
>>My compiler doesn't detect it. Is it
broken?
If you asked it to try to conform to the standard, then yes.
>>In the Standard I didn't find any restriction.
It's in 6.7p2: "A declaration shall declare at least a declarator (other
than the parameters of a function or the members of a structure or union),
a tag, or the members of an enumeration." Your declaration does not
declare any of those.
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