通过typeof获得x和y的数据类型然后定义两个临时变量并把x和y的值分别赋给这两个临时变量最后进行比较 C语言中的typeof 关键字typeof用于获取表达式的数据类型。只有部分编译器支持,这个特性在linux内核中应用非常广泛, 1. const typeof( ((type *)0)->member ) *__mptr = (ptr); 是定义一个__mptr指针...
1. container_of是Linux内核中实现的宏，不是C语言的标准函数。不能跨平台。define container_of(ptr, type, member) ({\ const typeof( ((type *)0)->member ) *__mptr = (ptr);\ (type *)( (char *)__mptr - offsetof(type,member) );})2. typeof是GNU C的扩展，不是ISO标准...
C 2023草案N3096 7.21 4说，offsetof(type,member-designator)：.如果指定的type定义了一个新的类型，...
member-designator 是结构体 type 中的成员。 求得member-designator 在结构体type中的偏移。
const typeof( ((type *)0)->member ) _mptr = (ptr); \ (type *)( (char *)_mptr - offsetof(type, member) ); }) 1. 2. 3. 4. 5. 它的主要作用就是:根据结构体某一成员的地址,获取这个结构体的首地址。根据宏定义我们可以看到,这个宏有三个参数,他们分别是: ...
int member1; double member2; } myStruct; typeof(myStruct.member1) structMemberType = 15; printf("Struct Member Type: %d\n", structMemberType); //使用typeof在宏中获取类型信息 print_size(int); print_size(double); print_size(char); return 0; } ``` 在这个例子中,`typeof`被用于声明...
6、eration members) are named integer constants, separated by commas.(2) DAY is an identifier that can be considered as the name of the collection, and is an optional, optional item.(3) the default value of the first enumerator member is 0 of the integer, and the value of the subseque...
memberName :Name of the member in the parent data structure for which to determine the offset. Return Value : offsetof returns the offset in bytes of the specified member from the beginning of its parent data structure. It is undefined for bit fields. ...
C 2023草案N3096 7.21 4说，offsetof(type,member-designator)：.如果指定的type定义了一个新的类型，...