前瞻性声明一个外部结构 [英] Forward-declaring an extern struct

问题描述

在我开始：

• 的请注意：的那个我不希望
  改变主要的设计我在这里是presenting你。


• 随意更改标题，如果你觉得这个人不适合以及


• C ++的标签是在这里，因为该解决方案应相当于为它以及

我有一个头 breakpoints.h 这声明：

typedef struct BreakpointInfo BreakpointInfo;

/*
 * Iterate all breakpoints known to the Breakpoints service,
 * including breakpoints that are created by other (remote) clients.
 */
typedef void IterateBreakpointsCallBack(BreakpointInfo *, void *);
extern void iterate_breakpoints(IterateBreakpointsCallBack * callback, void * args);

和相应的 breakpoints.c 定义：

struct BreakpointInfo {
    Context * ctx;
    LINK link_all;

    /*
     * A lot of members ..
     */

    LINK link_hit_count;
};

现在，我想在另一个文件中使用此functionallity context.c ：

Now I would like to use this functionallity in another file context.c:

#include <tcf/services/breakpoints.h> // The header file 

extern BreakpointInfo;
//extern struct BreakpointInfo; // Also did not work

void MyIterateBreakpointsCallBack(/* struct */ BreakpointInfo *bpInfo, void *args)
{
    bpInfo->file;
}

void thread_function() 
{
    // ..

    iterate_breakpoints(&MyIterateBreakpointsCallBack, 0);

    // ..
}

不过的Intelli-常识告诉我：

But Intelli-Sense tells me:

BreakpointInfo *bpInfo, Error: pointer to incomplete class type is not allowed.

所以，问题是：

• 是甚至可能的没有移动 BreakpointInfo 定义成头文件？

• Is that even possible without moving the definition of BreakpointInfo into the header file?

我不想改变这种状况，因为它是一个相当复杂的程序，我不希望做这样的事情，以打破其设计。

I don't want to change that since it is a quite complex program and I don't want to break its' design by doing such things.

这是可能的，我使用了错误的方式，但为什么会有BA一个 iterate_breakpoints（）供我来访问，如果我无法访问<函数code> BreakpointInfo ？

It may be possible that I am using it the wrong way but why would there ba a iterate_breakpoints() function available for me to access if I could not access BreakpointInfo?

我希望这是清楚我问。请让我知道如果你需要什么帮助我。

I hope it is clear what I am asking. Please let me know if you need anything to help me.

最好的问候。

推荐答案

我不认为这是可能的，因为在 MyIterateBreakpointsCallBack 你试图访问的成员键入并且这需要在这一点的完整类型。

I don't think it is possible since in MyIterateBreakpointsCallBack you're trying to access members of the type and this requires a complete type at this point.

我不熟悉，你想一起工作，但一个快速谷歌搜索我暗示其tcf.agent项目的项目。如果这是真的，咋一看在我注意到breakpoints.h文件后，有一个 get_breakpoint_attribute（），让您的名称/值对的列表。也许这应该给你你需要实现信息的 MyIterateBreakpointsCallBack（）。

I am not familiar with the project you're trying to work with but a quick google search hinted me its the tcf.agent project. If this is true, after a quick look in the breakpoints.h file I noticed that there is a get_breakpoint_attribute() that gives you a list of name/value pairs. Maybe that should give you the info you need to implement your MyIterateBreakpointsCallBack().

这篇关于前瞻性声明一个外部结构的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！