使用静态数组初始化常量struct对象

I recently came across the following code:

我最近遇到了以下代码：

    static const struct gaih gaih[] = {    
#if defined __UCLIBC_HAS_IPV6__    
    { PF_INET6, gaih_inet },    
#endif    
    { PF_INET, gaih_inet },    
#if 0   
    { PF_LOCAL, gaih_local },    
#endif    
    { PF_UNSPEC, NULL }    
};    



     struct gaih {    
            int family;    
            int (*gaih)(const char *name, const struct gaih_service *service,    
                    const struct addrinfo *req, struct addrinfo **pai);    
        };    


int func{    

const struct gaih *g = gaih;    

    }

I understand the meaning of constant and static . But I able to decipher the logic behind static initialization of the constant object in such a crude way. please clarify the reason or use of doing it this way

我理解常量和静态的含义。但我能够以如此粗暴的方式破译常量对象静态初始化背后的逻辑。请澄清这样做的原因或用法

2 个解决方案

#1

file.c seems to be a C file. Using static in C has two meanings:

file.c似乎是一个C文件。在C中使用static有两个含义：

Not on the stack (e.g. for variables inside functions that shall keep their value across several calls of the function)
不在堆栈上（例如，对于函数内部的变量，它们应该在函数的多次调用中保持它们的值）
Not exported from this module (for variables that shall not be provided as a symbol to the linker)
不从此模块导出（对于不应作为符号提供给链接器的变量）

In this case it seems to be the second one. The variable gaih shall not be exported (visible for the linker) static and it shall not be changed const. There is nothing crude.

在这种情况下，它似乎是第二个。变量gaih不应导出（对于链接器可见）静态，并且不应更改为const。没有什么粗糙的。

But to clarify further details the complete valid code would be needed. It seems to be a constant and static initialisation of an array of structs with just one entry. The variable g is just a pointer to this single entry.

但为了澄清更多细节，将需要完整的有效代码。它似乎只是一个条目的结构数组的恒定和静态初始化。变量g只是指向此单个条目的指针。

This example has some similarity with the struct gaih_addrtuple in nss.h which is a linked list of host names and IP addresses used for gethostbyname.

此示例与nss.h中的struct gaih_addrtuple有一些相似之处，nss.h是用于gethostbyname的主机名和IP地址的链接列表。

#2

The global variable gaih is defined as static, which means it is only visible in the current file, and const, which means it can't be modified once initialized.

全局变量gaih定义为static，这意味着它只在当前文件和const中可见，这意味着它一旦初始化就无法修改。

The local variable g is also defined as const, meaning it can't be changed. It is initialized with the address of the global gaih array, so g can be treated as an array in this context.

局部变量g也定义为const，意味着它不能被改变。它使用全局gaih数组的地址初始化，因此在此上下文中可以将g视为数组。

g can also be passed to another function, possibly in a different file. This allows the contents of gaih to be read outside of the current file which would not be allowed by attempting to reference gaih directly.

g也可以传递给另一个函数，可能在另一个文件中。这允许在当前文件之外读取gaih的内容，这是通过尝试直接引用gaih而不允许的。

#1