在预处理程序指令中结合##和_type

Question

What is the purpose of the usage thread##_type in this code snippet? I understand that underscore t (_t) is used as a convention for naming to identify types, as is underscore type (_type) , often in typedef statements. I also understand ## in macros indicate concatenation. Does _type has any purpose other than this? (like the usage of double underscore __FILE__ )?

#define THREAD_TYPE(thread)                         
typedef struct                                      \
{                                                   \
   pthread_t pthread;                               \
   int err;                                         \
} thread##_type;

Answer 1

_type在C中没有特殊含义。此代码_type作者选择的方式修饰名称，仅此而已。