C++ 如何在 C 中判断变量是否属于某种类型(比较两种类型)

到目前为止，在具有_Generic泛型 Select 的C11中可以获得变量的类型.它在编译时工作.

语法有点像switch.以下是一个样本(来自this answer):

    #define typename(x) _Generic((x),                                                 \
            _Bool: "_Bool",                  unsigned char: "unsigned char",          \
             char: "char",                     signed char: "signed char",            \
        short int: "short int",         unsigned short int: "unsigned short int",     \
              int: "int",                     unsigned int: "unsigned int",           \
         long int: "long int",           unsigned long int: "unsigned long int",      \
    long long int: "long long int", unsigned long long int: "unsigned long long int", \
            float: "float",                         double: "double",                 \
      long double: "long double",                   char *: "pointer to char",        \
           void *: "pointer to void",                int *: "pointer to int",         \
          default: "other")

要实际使用它进行编译时手动类型判断，您可以定义一个enum，其中包含您期望的所有类型，如下所示:

    enum t_typename {
        TYPENAME_BOOL,
        TYPENAME_UNSIGNED_CHAR,
        TYPENAME_CHAR,
        TYPENAME_SIGNED_CHAR,
        TYPENAME_SHORT_INT,
        TYPENAME_UNSIGNED_CHORT_INT,
        TYPENAME_INT,
        /* ... */
        TYPENAME_POINTER_TO_INT,
        TYPENAME_OTHER
    };

然后使用_Generic将类型与此enum匹配:

    #define typename(x) _Generic((x),                                                       \
            _Bool: TYPENAME_BOOL,           unsigned char: TYPENAME_UNSIGNED_CHAR,          \
             char: TYPENAME_CHAR,             signed char: TYPENAME_SIGNED_CHAR,            \
        short int: TYPENAME_SHORT_INT, unsigned short int: TYPENAME_UNSIGNED_SHORT_INT,     \
              int: TYPENAME_INT,                     \
        /* ... */                                    \
            int *: TYPENAME_POINTER_TO_INT,          \
          default: TYPENAME_OTHER)