'{'之前的预期类名 [英] expected class-name before '{'

问题描述

我有大约10个带有实现类的头文件。现在，当我尝试编译它们时，我会收到以下消息：

来自Proxy / ServerCnx.hh的文件：36，
$来自Proxy / Payload.hh的b $ b：30，

...
来自main.cc的


代理/接口.hh ：83：错误：在''{''

之前的预期类名.Interface.hh看起来像这样：

class模块：public ClientCnx {...}

到目前为止，我认为ClientCnx没有声明。所以我试图通过使用

类ClientCnx来生成前瞻性声明

;

但是现在，编译器说：

Proxy / Interface.hh：83：error_无效使用未定义类型`ClientCnx`


代理/接口.h.h：30：error_ forward声明'ClientCnx`

现在我可以做些什么来解决这个问题？！？

Hi,

i′ve got about 10 headerfiles with implemented classes. Now when i try

to compile them i get the following message:
In file included from Proxy/ServerCnx.hh:36,
from Proxy/Payload.hh:30,
...
from main.cc:28
Proxy/Interface.hh:83: error: expected class-name before ''{''
The Interface.hh looks like this:
class Module : public ClientCnx{...}
so far, i realisied that ClientCnx isn′t declarated. So I tried to
make a forward Declaration
by using
class ClientCnx;
but now, the compiler says:
Proxy/Interface.hh:83: error_ invalid use of undefined type `ClientCnx`

Proxy/Interface.hh:30: error_ forward declaration of `ClientCnx`
now what can i do to fix this prob ?!?

推荐答案

bubzilla写道：

bubzilla wrote:

i have有大约10个带有实现类的头文件。现在，当我尝试使用
来编译它们时，我收到以下消息：


在Proxy / ServerCnx.hh中包含的文件中：36，
$来自Proxy / Payload.hh的b $ b：30，

...
来自main.cc的


代理/接口.hh ：83：错误：在''{''

之前预期的类名称。接口.hh看起来像这样：


class模块： public ClientCnx {...}


到目前为止，我认为ClientCnx没有声明。所以我尝试使用


class ClientCnx;

Hi,

i′ve got about 10 headerfiles with implemented classes. Now when i try
to compile them i get the following message:

In file included from Proxy/ServerCnx.hh:36,
from Proxy/Payload.hh:30,
...
from main.cc:28
Proxy/Interface.hh:83: error: expected class-name before ''{''

The Interface.hh looks like this:

class Module : public ClientCnx{...}

so far, i realisied that ClientCnx isn′t declarated. So I tried to
make a forward Declaration
by using

class ClientCnx;

$ $

制作前瞻声明

b
$ b这里的前向声明是不够的，编译器需要看到基类的整个声明

。

A forward declaration isn''t sufficient here, the compiler needs to see
the whole declaration of the base classes.

>

但是现在，编译器说：


代理/接口.h.h：83：error_无效使用未定义类型`ClientCnx`


代理/接口.hh：30：错误_提前声明`ClientCnx`


现在我可以做些什么来解决这个问题？ ？

>
but now, the compiler says:

Proxy/Interface.hh:83: error_ invalid use of undefined type `ClientCnx`

Proxy/Interface.hh:30: error_ forward declaration of `ClientCnx`
now what can i do to fix this prob ?!?

找到声明基类的头文件，并在

模块声明之前包含它。


问候，

Stuart

Find the header file that declares the base class and include it before
the declaration of Module.

Regards,
Stuart

bubzilla写道：

bubzilla wrote:

i已经有大约10个带有实现类的头文件。现在，当我尝试编译它们时，我得到以下消息：


在Proxy / ServerCnx.hh中包含的文件中：36，<来自Proxy / Payload.hh的
：30，

...

from main.cc:28

代理/Interface.hh:83：错误：在''{''


之前的预期类名.Interface.hh看起来像这样：


class Module：public ClientCnx {...}


到目前为止，我实现了ClientCnx没有声明。

Hi,

i′ve got about 10 headerfiles with implemented classes. Now when i try

to compile them i get the following message:
In file included from Proxy/ServerCnx.hh:36,
from Proxy/Payload.hh:30,
...
from main.cc:28
Proxy/Interface.hh:83: error: expected class-name before ''{''
The Interface.hh looks like this:
class Module : public ClientCnx{...}
so far, i realisied that ClientCnx isn′t declarated.

这肯定听起来像是一个合理的结论。

That certainly sounds like a reasonable conclusion.

所以我试图做出前瞻声明

So I tried to make a forward Declaration

但为什么你认为前瞻性声明有帮助？

But why do you think a forward declaration would help?

使用


类ClientCnx;


但是现在，编译器说：


Proxy / Interface.hh:83:error_ invalid use未定义的类型`ClientCnx`


代理/接口.h.h：30：错误_客户端解密`ClientCnx`


现在该怎么办？解决这个问题？！？

by using
class ClientCnx;
but now, the compiler says:
Proxy/Interface.hh:83: error_ invalid use of undefined type `ClientCnx`

Proxy/Interface.hh:30: error_ forward declaration of `ClientCnx`
now what can i do to fix this prob ?!?

ClientCnx是Module的基类，编译器在看到Module之前需要知道ClientCnx的完整定义。前向

声明只告诉编译器ClientCnx是

类的名称。这还不够。您需要包含ClientCnx的整个类

定义。如果ClientCnx是在标题中定义的，那么#include

那个标题高于类Module的定义。


Gavin Deane

ClientCnx is a base class of Module and the compiler needs to know the
full definition of ClientCnx before it sees Module. A forward
declaration just tells the compiler that ClientCnx is the name of a
class. That is not enough. You need to include the entire class
definition of ClientCnx. If ClientCnx is defined in a header, #include
that header above the definition of class Module.

Gavin Deane

好的，我有同样的解决方案。所以我试图更改标题包括，

但是有些我怎么做到了没有错误出现的方式！


所以，我必须尝试再次，找到合适的包括订单。


或者可能是因为有一些圈子需要以其他方式解决？
a？ />
我不熟悉编译器如何将头文件放在一起？

Ok, i had the same solution. So i tried to change the header includes,
but some how i did got a way so that no error appears!

so, do i have to try again, to find the right include order.

Or can it be that there is somekind of circle that has to be solved in
a other way?
I''m not familiar how the Compiler brings the headerfiles together?

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