typedef的问题 [英] Problems with typedef
问题描述
大家好，
我对以下内容感到困惑，这导致我们的用户之一
's代码编译失败：
typedef struct SctpDest_S;
1）这是标准吗？
2）如果是这样（或者即使不是这样！）该怎么办？
错误信息是
" A typedef声明必须声明一个名称。
这似乎有意义！很抱歉，如果我错过了明显的
，但它与常见问题解答中的1.17无关，是吗？
基于类似的理由，他有typedef的表格
typedef struct SctpHeartbeatChunk_S
{
SctpChunkHdr_S sHdr;
u_short usInfoType;
u_short usInfoLength;
double dTimestamp;
SctpDest_S * spDest;
};
再次是这个标准，它应该做什么？ （虽然这一次
我可能会猜到）
对不起，如果这很明显，看看K& R2我找不到它C非常多b / b
我的第二语言（我是Fortran家伙），
Ian
Hi All,
I''m a bit confused by the following which is causing one of
our user''s codes fail in compilation:
typedef struct SctpDest_S;
1) Is this standard ?
2) If so ( or even if not so ! ) what is it supposed to do ?
The error message is
"A typedef declaration must declare a name."
which seems to make sense ! Sorry if I missing the obvious
but it''s not related to 1.17 in the FAQ, is it ?
On similar grounds he has typedefs of the form
typedef struct SctpHeartbeatChunk_S
{
SctpChunkHdr_S sHdr;
u_short usInfoType;
u_short usInfoLength;
double dTimestamp;
SctpDest_S *spDest;
};
Again is this standard and what is it supposed to do ? ( though this time
I might be able to guess )
Sorry if this is obvious, looking in K&R2 I can''t find it and C is very much
my second language (I''m a Fortran guy),
Ian
推荐答案
伊恩·布什写道：
我对以下内容感到困惑，导致其中一个用户的代码在编译时失败：
typedef struct SctpDest_S;
1）这是标准吗？
2）如果是这样（或者即使不是这样！）它应该做什么？
错误信息是
typedef声明必须声明一个名称。
这似乎有意义！对不起，如果我错过了明显的
但它与常见问题解答中的1.17无关，是吗？
typedef为现有的
类型创建一个新名称（我称之为同义词），因此您需要提供两个名称，旧的和新的。
你只给一个：SctpDest_S
它应该是
typedef struct SctpDest_S new_name;
或
typedef struct old_name SctpDest_S;
基于类似理由他有形式的typedef
typedef struct SctpHeartbeatChunk_S
{sctpChunkHdr_S sHdr;
u_short usInfoType;
u_short usInfoLength;
double dTimestamp;
SctpDest_S * spDest;
};
这个标准又是什么呢？它应该做什么？ （虽然这次我可能会猜到）
对不起，如果这是显而易见的，看看K& R2我找不到它而且C非常多
我的第二语言（我是Fortran家伙），
I''m a bit confused by the following which is causing one of
our user''s codes fail in compilation:
typedef struct SctpDest_S;
1) Is this standard ?
2) If so ( or even if not so ! ) what is it supposed to do ?
The error message is
"A typedef declaration must declare a name."
which seems to make sense ! Sorry if I missing the obvious
but it''s not related to 1.17 in the FAQ, is it ?
A typedef creates a new name (I call it a "synonym") for an existing
type, so you need to provide two names, the old and the new.
You are giving only one: SctpDest_S
It should be either
typedef struct SctpDest_S new_name;
or
typedef struct old_name SctpDest_S;
On similar grounds he has typedefs of the form
typedef struct SctpHeartbeatChunk_S
{
SctpChunkHdr_S sHdr;
u_short usInfoType;
u_short usInfoLength;
double dTimestamp;
SctpDest_S *spDest;
};
Again is this standard and what is it supposed to do ? ( though this time
I might be able to guess )
Sorry if this is obvious, looking in K&R2 I can''t find it and C is very much
my second language (I''m a Fortran guy),
Roberto Waltman写道：
Roberto Waltman wrote:
Ian Bush写道：
Ian Bush wrote:
我对以下内容感到困惑，导致我们用户的代码之一在编译时失败：
typedef struct SctpDest_S;
1）这是标准吗？
2）如果是这样（或者即使不是这样！）该怎么办？
错误信息是
一个typedef声明必须声明一个名称。
这似乎有意义！很抱歉，如果我错过了明显的
但它与FAQ中的1.17无关，是吗？
I''m a bit confused by the following which is causing one of
our user''s codes fail in compilation:
typedef struct SctpDest_S;
1) Is this standard ?
2) If so ( or even if not so ! ) what is it supposed to do ?
The error message is
"A typedef declaration must declare a name."
which seems to make sense ! Sorry if I missing the obvious
but it''s not related to 1.17 in the FAQ, is it ?
一个typedef创建一个新名称（我称之为 ;同义词"）对于现有的
类型，所以你需要提供两个名称，旧的和新的。
你只给一个：SctpDest_S
它应该是
typedef struct SctpDest_S new_name;
typedef struct old_name SctpDest_S;
A typedef creates a new name (I call it a "synonym") for an existing
type, so you need to provide two names, the old and the new.
You are giving only one: SctpDest_S
It should be either
typedef struct SctpDest_S new_name;
or
typedef struct old_name SctpDest_S;
是的，我理解这一点。然而，我的用户没有，我想知道是否在
任何情况下它可能意味着什么，如果是这样的话是什么情况
这是什么意思？
谢谢，
Ian
Yes, I understand this. However my user has not and I am wondering if under
any circumstances it may mean anything, and if so what are those circumstances
and what does it mean ?
Thanks,
Ian
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哈希：SHA1
Roberto Waltman写道：
-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1
Roberto Waltman wrote:
Ian Bush写道：
Ian Bush wrote:
我对以下内容感到有点困惑，这导致我们的用户代码之一在编译时失败：
typedef struct SctpDest_S;
1）这是标准吗？
2）如果是这样（或者即使不是这样！）该怎么办？
错误信息是
A typedef声明必须声明一个名称。
这似乎有意义！对不起，如果我错过了明显的
但它与常见问题解答中的1.17无关，是吗？
一个typedef为现有的<创建一个新名称（我称之为同义词） br />类型，所以你需要提供两个名称，旧的和新的。
I''m a bit confused by the following which is causing one of
our user''s codes fail in compilation:
typedef struct SctpDest_S;
1) Is this standard ?
2) If so ( or even if not so ! ) what is it supposed to do ?
The error message is
"A typedef declaration must declare a name."
which seems to make sense ! Sorry if I missing the obvious
but it''s not related to 1.17 in the FAQ, is it ?
A typedef creates a new name (I call it a "synonym") for an existing
type, so you need to provide two names, the old and the new.
ITYM
所以你需要提供一个类型和名称。
你只给一个：SctpDest_S
ITYM
"你只给名称
应该是
typedef struct SctpDest_S new_name;
，其中包含类型struct SctpDest_S"和一个名称new_name
或
typedef struct old_name SctpDest_S;
ITYM
"so you need to provide a type and a name".
You are giving only one: SctpDest_S
ITYM
"You are giving only the name"
It should be either
typedef struct SctpDest_S new_name;
which contains a type "struct SctpDest_S" and a name "new_name"
or
typedef struct old_name SctpDest_S;
包含一个类型" ; struct old_name"和一个名字SctpDest_S
which contains a type "struct old_name" and a name "SctpDest_S"
基于类似的理由，他有类型的typedef
typedef struct SctpHeartbeatChunk_S {
SctpChunkHdr_S sHdr;
u_short usInfoType;
u_short usInfoLength;
double dTimestamp;
SctpDest_S * spDest;
};
，其类型为struct SctpHeartbeatChunk_S {...}但没有名字。
这个标准又是什么呢？它应该做什么？ （虽然这次我可能会猜到）
AFAIK，这不是标准，也不应该编译。这是一个
不完整的typedef，缺少给定类型的typedef名称。
对不起，如果这很明显，看看K& R2我可以'找不到它，C非常多我的第二语言（我是Fortran家伙），
On similar grounds he has typedefs of the form
typedef struct SctpHeartbeatChunk_S
{
SctpChunkHdr_S sHdr;
u_short usInfoType;
u_short usInfoLength;
double dTimestamp;
SctpDest_S *spDest;
};
which has a type of "struct SctpHeartbeatChunk_S { ... }" but no name.
Again is this standard and what is it supposed to do ? ( though this time
I might be able to guess )
AFAIK, this isn''t standard, and it should not compile. It is an
incomplete typedef, lacking a name to be typedef''ed to the given type.
Sorry if this is obvious, looking in K&R2 I can''t find it and C is very much
my second language (I''m a Fortran guy),
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