是否有满足C99标准的static_assert替代品? [英] Is there a static_assert replacement which satisfies the C99 standard?

问题描述

我一直在尝试实现类似于C ++ 11标准中定义的 static_assert 的方法.主要问题是C ++编译器如何将传递到 static_assert 的文本消息作为 const char * 编写?我可以让编译器编写诸如 A_is_not_POD 之类的消息.这就是我所拥有的:

I have been trying to implement a method similar to static_assert which is defined in the C++11 standard. The main problem is how does the C++ compiler write the text message being passed to static_assert as a const char*? I can get the compiler to write a message like A_is_not_POD. This is what I have:

#define MY_STATIC_ASSERT(condition, name)         \
   typedef char name[(condition) ? 1 : -1]; 

但是让编译器编写类似错误:A不是POD." 有什么建议吗?

But it would be quite nice to get the compiler to write something like "Error: A is not POD." Any suggestions?

推荐答案

我不确定我是否理解问题，但是C11具有 _Static_assert(condition，errmessage).在C99中，缺少此功能，但是根据编译器的不同，有可能进行仿真.例如.for gcc(不幸的是clang不支持attribute(error))

Not sure i understand question, but C11 have _Static_assert(condition, errmessage). In C99 this functionality was missing but, depending on compiler, it could be possible to emulate. E.g. for gcc (unfortulately clang doesn't support attribute(error))

#define MY_STATIC_ASSERT(cnd, descr) ({ \
    extern int __attribute__ ((error("static assert failed: (" #cnd ") (" #descr ")"))) \
               compile_time_check(void); \
    ((cnd) ? 0 : compile_time_check()), 0; \
})

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