c++ - #警告和宏观评价

Question

我有以下代码:

#define LIMIT_DATE \"01-03-2010\"

#ifdef LIMIT_DATE
    #if _MSC_VER
        #pragma message ("Warning : this release will expire on " LIMIT_DATE)
    #elif   __GNUC__
        #warning ("Warning : this release will expire on " LIMIT_DATE)
    #endif
#endif

问题是在打印警告时未评估 LIMIT_DATE。

我在 Google 上搜索过，但还没有找到解决方案。

感谢您的帮助。

Answer 1

From gcc preprocessor documentation

Neither #error nor #warning macro-expands its argument. Internal whitespace sequences are each replaced with a single space. The line must consist of complete tokens. It is wisest to make the argument of these directives be a single string constant; this avoids problems with apostrophes and the like.

所以至少在 gcc 中是不可能的。

根据 MSDN这应该适用于 MSVC，尽管我目前无法访问 Visual Studio 来测试它