blocks|key|2832139|text|您需要查看转发声明，您已经创建了包含的无限循环，前向声明是正确的解决方案。|type|unstyled|depth|inlineStyleRanges|offset|length|style|BOLD|entityRanges|data|2832140|下面是一个例子：|2832141|Move.h|2832142|#ifndef+MOVE_H_
#define+MOVE_H_

struct+board;+/*+forward+declaration+*/
struct+move+{
++++struct+board+*m_board;+/*+note+it's+a+pointer+so+the+compiler+doesn't+
++++++++++++++++++++++++++++*+need+the+full+definition+of+struct+board+yet...+
++++++++++++++++++++++++++++*+make+sure+you+set+it+to+something!*/
};
#endif|code-block|syntax|javascript|2832143|Board.h|2832144|#ifndef+BOARD_H_
#define+BOARD_H_

#include+"Move.h"
struct+board+{
++++struct+move+m_move;+/*+one+of+the+two+can+be+a+full+definition+*/
};
#endif|2832145|main.c|2832146|#include+"Board.h"
int+main()+{+...+}|2832147|注意:每当创建“委员会”时，您都需要这样做(有几种方法，下面是一个例子)：|2832148|struct+board+*b+=+malloc(sizeof(struct+board));
b->m_move.m_board+=+b;+/*+make+the+move's+board+point+
++++++++++++++++++++++++*+to+the+board+it's+associated+with+*/|2832149|entityMap^0|5|4|0|0|0|0|0|0|0|0|0|11|0|0^^$0|@$1|2|3|4|5|6|7|12|8|@$9|13|A|14|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|15|8|@]|D|@]|E|$]]|$1|H|3|I|5|6|7|16|8|@]|D|@]|E|$]]|$1|J|3|K|5|L|7|17|8|@]|D|@]|E|$M|N]]|$1|O|3|P|5|6|7|18|8|@]|D|@]|E|$]]|$1|Q|3|R|5|L|7|19|8|@]|D|@]|E|$M|N]]|$1|S|3|T|5|6|7|1A|8|@]|D|@]|E|$]]|$1|U|3|V|5|L|7|1B|8|@]|D|@]|E|$M|N]]|$1|W|3|X|5|6|7|1C|8|@$9|1D|A|1E|B|C]]|D|@]|E|$]]|$1|Y|3|Z|5|L|7|1F|8|@]|D|@]|E|$M|N]]|$1|10|3|-4|5|6|7|1G|8|@]|D|@]|E|$]]]|11|$]]

You need to look into forward declarations, you have created an infinite loops of includes, forward declarations are the proper solution.

Here's an example:

Move.h

<pre><code>#ifndef MOVE_H_
#define MOVE_H_

struct board; /* forward declaration */
struct move {
 struct board *m_board; /* note it's a pointer so the compiler doesn't 
 * need the full definition of struct board yet... 
 * make sure you set it to something!*/
};
#endif
</code></pre>

Board.h

<pre><code>#ifndef BOARD_H_
#define BOARD_H_

#include "Move.h"
struct board {
 struct move m_move; /* one of the two can be a full definition */
};
#endif
</code></pre>

main.c

<pre><code>#include "Board.h"
int main() { ... }
</code></pre>

Note: whenever you create a "Board", you will need to do something like this (there are a few ways, here's an example):

<pre><code>struct board *b = malloc(sizeof(struct board));
b-&gt;m_move.m_board = b; /* make the move's board point 
 * to the board it's associated with */
</code></pre>

blocks|key|1309081|text|你得先吃一杯。在其中一个中做一个前倾，例如有那个。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1309082|++++#ifndef+move
++++struct+move;
++++#endif|code-block|syntax|javascript|1309083|可能是board.h文件的一部分。|1309084|和|1309085|++++#ifndef+board
++++struct+board;
++++#endif|1309086|可能是move.h文件的一部分|1309087|然后你可以按两种顺序加起来。|1309088|正如评论中指出的那样，编辑.我假设在板结构中使用typedef结构如下所示|offset|length|style|BOLD|1309089|+++typedef+struct+{…}+board;|1309090|因为我从来没有见过在C中使用结构而没有类型的人，所以我做了这个假设..。也许自从上次我用C编码以后，事情变了.大概15年前)|1309091|entityMap^0|0|0|0|0|0|0|0|B|2|0|0|0^^$0|@$1|2|3|4|5|6|7|12|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|13|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|14|8|@]|9|@]|A|$]]|$1|I|3|J|5|6|7|15|8|@]|9|@]|A|$]]|$1|K|3|L|5|D|7|16|8|@]|9|@]|A|$E|F]]|$1|M|3|N|5|6|7|17|8|@]|9|@]|A|$]]|$1|O|3|P|5|6|7|18|8|@]|9|@]|A|$]]|$1|Q|3|R|5|6|7|19|8|@$S|1A|T|1B|U|V]]|9|@]|A|$]]|$1|W|3|X|5|D|7|1C|8|@]|9|@]|A|$E|F]]|$1|Y|3|Z|5|6|7|1D|8|@]|9|@]|A|$]]|$1|10|3|-4|5|6|7|1E|8|@]|9|@]|A|$]]]|11|$]]

You need to have one of them first. Make a forward decl in one of them and have that one for for example

<pre><code> #ifndef move
 struct move;
 #endif
</code></pre>

could be part of the board.h file.

and

<pre><code> #ifndef board
 struct board;
 #endif
</code></pre>

could be part of the move.h file

then you could add them in either order.

edit
As was pointed out in the comments... I was assuming the use of the typedef construct as follows for the board struct

<pre><code> typedef struct {…} board;
</code></pre>

since I've never seen anyone using structs in C without a typedef I made this assumption... maybe things have changed since the last time I coded in C (yikies.... it was like 15 years ago)

blocks|key|1309098|text|就像这样：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1309099|//Board.h
#ifndef+BOARD_H
#define+BOARD_H
strunct+move_t;+//forward+declaration
typedef+struct+move_t+Move;
//...
#endif+//BOARD_H

//Move.h
#ifndef+MOVE_H
#define+MOVE_H
#include+"Move.h"
typedef+struct+board_t+Board;
//...
#endif+//MOVE_H|code-block|syntax|javascript|1309100|通过这种方式可以编译Board.h而不依赖于move.h，并且可以从move.h中包含board.h以使其内容在那里可用。|offset|length|style|CODE|1309101|entityMap^0|0|0|A|7|M|6|Y|6|17|7|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|Q|8|@$I|R|J|S|K|L]|$I|T|J|U|K|L]|$I|V|J|W|K|L]|$I|X|J|Y|K|L]]|9|@]|A|$]]|$1|M|3|-4|5|6|7|Z|8|@]|9|@]|A|$]]]|N|$]]

Like so:

<pre><code>//Board.h
#ifndef BOARD_H
#define BOARD_H
strunct move_t; //forward declaration
typedef struct move_t Move;
//...
#endif //BOARD_H

//Move.h
#ifndef MOVE_H
#define MOVE_H
#include "Move.h"
typedef struct board_t Board;
//...
#endif //MOVE_H
</code></pre>

This way <code>Board.h</code> can be compiled without dependency on <code>move.h</code> and you can include <code>board.h</code> from <code>move.h</code> to make its content available there.

blocks|key|2832212|text|包括警卫将是解决这一问题的一部分。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2832213|维基百科的例子：|2832214|#ifndef+GRANDFATHER_H
#define+GRANDFATHER_H

struct+foo+{
++++int+member;
};

#endif|code-block|syntax|javascript|2832215|守卫|offset|length|2832216|另一部分，正如其他几个人所指出的，是向前参照。(参考文献)|2832217|您可以部分地将其中一个结构声明在另一个之上，如下所示：|2832218|#ifndef+GRANDFATHER_H
#define+GRANDFATHER_H

struct+bar;
struct+foo+{
++++int+member;
};

#endif|2832219|entityMap|0|LINK|mutability|MUTABLE|url|http://en.wikipedia.org/wiki/Include_guard|1|http://en.wikipedia.org/wiki/Forward_Reference^0|0|0|0|0|2|0|0|O|4|1|0|0|0^^$0|@$1|2|3|4|5|6|7|12|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|13|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|14|8|@]|9|@]|A|$G|H]]|$1|I|3|J|5|6|7|15|8|@]|9|@$K|16|L|17|1|18]]|A|$]]|$1|M|3|N|5|6|7|19|8|@]|9|@$K|1A|L|1B|1|1C]]|A|$]]|$1|O|3|P|5|6|7|1D|8|@]|9|@]|A|$]]|$1|Q|3|R|5|F|7|1E|8|@]|9|@]|A|$G|H]]|$1|S|3|-4|5|6|7|1F|8|@]|9|@]|A|$]]]|T|$U|$5|V|W|X|A|$Y|Z]]|10|$5|V|W|X|A|$Y|11]]]]

Include guards would be part of the solution to this issue.

Example from wikipedia:

<pre><code>#ifndef GRANDFATHER_H
#define GRANDFATHER_H

struct foo {
 int member;
};

#endif
</code></pre>

<a href="http://en.wikipedia.org/wiki/Include_guard" rel="nofollow noreferrer">http://en.wikipedia.org/wiki/Include_guard</a>

The other part as noted by several others is forward referencing. (<a href="http://en.wikipedia.org/wiki/Forward_Reference" rel="nofollow noreferrer">http://en.wikipedia.org/wiki/Forward_Reference</a>)

You can partially declare one of the structures above the other one like so:

<pre><code>#ifndef GRANDFATHER_H
#define GRANDFATHER_H

struct bar;
struct foo {
 int member;
};

#endif
</code></pre>

blocks|key|1183414|text|来自K&R的C编程语言(我的副本中有91页“条件包含”)，并为您做了一些调整：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1183415|#if+!defined+(BOARD_H)
#define+BOARD_H

/*+contents+of+board.h+go+here+*/

#endif|code-block|syntax|javascript|1183416|Move.h也是如此|1183417|这样，一旦包含了一次头，就不会再次包含它，因为“BOARD_H”名称已经为预处理器定义了。|1183418|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|N|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|O|8|@]|9|@]|A|$]]|$1|I|3|J|5|6|7|P|8|@]|9|@]|A|$]]|$1|K|3|-4|5|6|7|Q|8|@]|9|@]|A|$]]]|L|$]]

From K&amp;R The C Programming Language (p 91 "Conditional Inclusion" in my copy), with some tweaks for you:

<pre><code>#if !defined (BOARD_H)
#define BOARD_H

/* contents of board.h go here */

#endif
</code></pre>

and the same for Move.h

In this way, once a header has been included once, it will not be included again, as the 'BOARD_H' name has already been defined for the preprocessor.

blocks|key|1184448|text|首先，您似乎在您的包括警卫文件中缺少了.h，所以您需要递归地包含它们。那太糟了。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1184449|第二，您可以做一个前向声明。在Move.h中|1184450|/*+Include+guard+to+make+sure+your+header+files+are+idempotent+*/
#ifndef+H_MOVE_
#define+H_MOVE_

#include+"Board.h"

/*+Now+you+can+use+struct+Board+*/
struct+Move+{+struct+Board+*board;+};

#endif|code-block|syntax|javascript|1184451|在Board.h中|1184452|#ifndef+H_BOARD_
#define+H_BOARD_

struct+Move;+/*+Forward+declaration.++YOu+can+use+a+pointer+to
++++++++++++++++struct+Move+from+now+on,+but+the+type+itself+is+incomplete,
++++++++++++++++so+you+can't+declare+an+object+of+the+type+itself.+*/
struct+Board+{+struct+Move+*move;+};+/*+OK:+since+move+is+a+pointer+*/

#endif|1184453|请注意，如果需要在两个文件中声明struct+Move和struct+Board对象(而不是指向它们之一的指针)，则此方法将无法工作。这是因为其中一个类型在解析其中一个文件时是一个不完整的类型(在上面的示例中是struct+Move)。|1184454|因此，如果您需要在这两个文件中使用这些类型，就必须分离类型定义:有定义struct+Move和struct+Board的头文件，没有其他的(类似我上面的例子)，然后使用引用struct+Move和struct+Board的另一个头文件。|1184455|当然，您不能让struct+Move同时包含struct+Board和struct+Board包含struct+Move+--这将是无限递归，而且结构大小也是无限的！|1184456|entityMap|0|LINK|mutability|MUTABLE|url|http://en.wikipedia.org/wiki/Include_guard^0|J|2|9|4|0|0|F|6|0|0|1|7|0|0|G|B|S|C|2X|B|0|Z|B|1B|C|2E|B|2Q|C|0|7|B|M|C|Z|C|1D|B|0^^$0|@$1|2|3|4|5|6|7|14|8|@$9|15|A|16|B|C]]|D|@$9|17|A|18|1|19]]|E|$]]|$1|F|3|G|5|6|7|1A|8|@$9|1B|A|1C|B|C]]|D|@]|E|$]]|$1|H|3|I|5|J|7|1D|8|@]|D|@]|E|$K|L]]|$1|M|3|N|5|6|7|1E|8|@$9|1F|A|1G|B|C]]|D|@]|E|$]]|$1|O|3|P|5|J|7|1H|8|@]|D|@]|E|$K|L]]|$1|Q|3|R|5|6|7|1I|8|@$9|1J|A|1K|B|C]|$9|1L|A|1M|B|C]|$9|1N|A|1O|B|C]]|D|@]|E|$]]|$1|S|3|T|5|6|7|1P|8|@$9|1Q|A|1R|B|C]|$9|1S|A|1T|B|C]|$9|1U|A|1V|B|C]|$9|1W|A|1X|B|C]]|D|@]|E|$]]|$1|U|3|V|5|6|7|1Y|8|@$9|1Z|A|20|B|C]|$9|21|A|22|B|C]|$9|23|A|24|B|C]|$9|25|A|26|B|C]]|D|@]|E|$]]|$1|W|3|-4|5|6|7|27|8|@]|D|@]|E|$]]]|X|$Y|$5|Z|10|11|E|$12|13]]]]

First, you seem to lack <a href="http://en.wikipedia.org/wiki/Include_guard" rel="nofollow noreferrer">include guards</a> in your <code>.h</code> files, so you're including them recursively. That is bad.

Second, you can do a forward declaration. In <code>Move.h</code>:

<pre><code>/* Include guard to make sure your header files are idempotent */
#ifndef H_MOVE_
#define H_MOVE_

#include "Board.h"

/* Now you can use struct Board */
struct Move { struct Board *board; };

#endif
</code></pre>

In <code>Board.h</code>:

<pre><code>#ifndef H_BOARD_
#define H_BOARD_

struct Move; /* Forward declaration. YOu can use a pointer to
 struct Move from now on, but the type itself is incomplete,
 so you can't declare an object of the type itself. */
struct Board { struct Move *move; }; /* OK: since move is a pointer */

#endif
</code></pre>

Note that if you need to declare <code>struct Move</code> and <code>struct Board</code> objects (rather than pointer to one of them) in both the files, this method won't work. This is because one of the types is an incomplete type at the time of parsing of one of the files (<code>struct Move</code> in the above example).

So, if you need to use the types in both the files, you will have to separate out the type definitions: have header files that define <code>struct Move</code> and <code>struct Board</code>, and nothing else (something like my example above), and then use another header file that references both <code>struct Move</code> and <code>struct Board</code>.

Of course, you can't have <code>struct Move</code> contain a <code>struct Board</code> and <code>struct Board</code> contain a <code>struct Move</code> at the same time&mdash;that will be infinite recursion, and the struct sizes will be infinite as well!

blocks|key|2832385|text|循环依赖是一个痛苦的问题，应该在可行的情况下消除。除了到目前为止给出的前瞻性声明建议(Alok是最好的例子)之外，我还想提出另一个建议:打破董事会之间的相互依赖，引入第三种类型(请将其命名为BoardMoveAssoc；我相信您可以想出一个不那么糟糕的名称)：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2832386|#ifndef+H_BOARD_MOVE_ASSOC
#define+H_BOARD_MOVE_ASSOC

#include+"Move.h"
#include+"Board.h"

struct+BoardMoveAssoc+{
++++Move+m;
++++Board+b;
};

...
#endif|code-block|syntax|javascript|2832387|在此方案下，委员会和移动不必相互了解任何信息；两者之间的任何关联都由BoardMoveAssoc类型管理。确切的结构将取决于移动和董事会应该如何关联；例如，如果多个移动被映射到一个单板上，结构看起来可能更像|2832388|+struct+BoardMoveAssoc+{
+++++Move+m[NUM_MOVES]+//+or+Move+*m;
+++++Board+b;
+};|2832389|这样，您就不必担心前向声明或不完整的类型。您正在引入第三种类型的混合，但我相信这将更容易理解和维护。|2832390|entityMap^0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|Q|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|R|8|@]|9|@]|A|$E|F]]|$1|K|3|L|5|6|7|S|8|@]|9|@]|A|$]]|$1|M|3|-4|5|6|7|T|8|@]|9|@]|A|$]]]|N|$]]

Circular dependencies are a pain in the ass and should be eliminated wherever feasible. In addition to the forward declaration suggestions given so far (Alok's is the best example), I'd like to throw another suggestion into the works: break the mutual dependency between Board and Move by introducing a third type (call it BoardMoveAssoc for illustration; I'm sure you can come up with a less sucky name):

<pre><code>#ifndef H_BOARD_MOVE_ASSOC
#define H_BOARD_MOVE_ASSOC

#include "Move.h"
#include "Board.h"

struct BoardMoveAssoc {
 Move m;
 Board b;
};

...
#endif
</code></pre>

Under this scheme, Board and Move don't have to know anything about each other; any associations between the two are managed by the BoardMoveAssoc type. The exact structure will depend on how Move and Board are supposed to be related; e.g., if multiple moves are mapped to a single board, the structure may look more like

<pre><code> struct BoardMoveAssoc {
 Move m[NUM_MOVES] // or Move *m;
 Board b;
 };
</code></pre>

This way, you don't have to worry about forward declarations or incomplete types. You are introducing a third type into the mix, but I believe this will be easier to understand and maintain.

I roughly understand the rules with what #include does with the C preprocessor, but I don't understand it completely. Right now, I have two header files, Move.h and Board.h that both typedef their respective type (Move and Board). In both header files, I need to reference the type defined in the other header file.

Right now I have #include "Move.h" in Board.h and #include "Board.h" in Move.h. When I compile though, gcc flips out and gives me a long (what looks like infinite recursive) error message flipping between Move.h and Board.h.

How do I include these files so that I'm not recursively including indefinitely?

Preventing recursive C #include

翻译质量差，导致语言生硬或混乱。

没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

页面排版不美观，阅读体验差。

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我大致理解了使用C预处理器所做的#include做什么规则，但我并不完全理解它。现在，我有两个头文件，Move.h和Board.h，这两个文件都是属于它们各自的类型(Move和Board)。在两个头文件中，我需要引用在另一个头文件中定义的类型。现在，我在Board.h中有#include " Move.h“，在move...

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