问题描述
大家好，
是否有效：
struct test {
};
我的意思是，我们可以有一个不包含成员的结构吗？这是一个
不完整类型？
请提供您的专家意见。
谢谢，
Raman Chalotra
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
推荐答案
我没有看到声明有什么问题。虽然这些东西
看起来不像它可以有任何实际的应用程序。
标准不要求在结构中声明成员。这个
代码在Linux / gcc上用''-ansi'标志编译。
我看不出它为什么不应该有效的原因。
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.
< snip>
<snip>
我没有看到声明有什么问题。虽然这些东西
看起来不像它可以有任何实际的应用程序。
标准不要求在结构中声明成员。
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.
我的副本有。语法指定必须至少有一个
成员。你从哪里得到你的信息？
My copy does. The syntax specifies that there must be at least one
member. Where are you getting your information from?
添加-pedantic。
Add -pedantic.
-
Ben。
--
Ben.
No.
No.
No.
No.
我没有看到声明有什么问题。
I don''t see anything wrong with the declaration.
然后你需要更仔细地看一下标准：
6.7.2.1结构和联合说明符
语法
1 struct-or-union-specifier：
struct-or-union identifieropt {struct-declaration-list}
struct-or -union标识符
struct-or-union：
struct
union
struct-declaration-list：
struct-declaration
struct-declaration-list struct-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!
错误。从N1256开始：
Wrong. From N1256:
这并不能使其获得所有必需的诊断。你需要''-ansi
-pedantic''，此时它会发出警告。请注意，警告是足以满足无效标准要求的b $ b。代码（一个puch
的面孔也可以获得资格，但我不认为这个实现会这样做会非常受欢迎）
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)
见上文。
不完整类型将是
struct test;
-
Flash Gordon
See above.
An imcomplete type would be
struct test;
--
Flash Gordon
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