C中的struct中使用的函数指针

Question

Could anyone explain the following syntax of code for structures in C ?

struct { 
  Fn *pmq;
}
service_MQ[] = 
{
   NULL
   #define BUILd_SVC_MQ(name , func) , (Fn*) Func
   #include<mqsvctable.h>
};

Answer 1

• There is a structure with only member as a pointer (possibly to a function)
• There is an x-header file mqsvctable.h containing list of functions under BUILd_SVC_MQ macro. Something like

BUILd_SVC_MQ("clear", clear_screen)
BUILd_SVC_MQ("delete", delete_something)

• You use this x-macro header to prepare an array of your struct.