struct x vs x_t in C

Question

In my recent operating systems class we have a bunch of objects defined as such:

typedef struct someobj {
  ... stuff ...
} someobj_t;

I know what that does just fine.

The question is that sometimes in the given support code the structs were refered to as struct someobj *some, and sometimes as someobj_t *some. Is there an actual/useful reason to refer to structs in these two different ways, or is just a stylistic difference?

Answer 1

虽然由您决定是使用typedef还是结构名称,但是有一个很好的理由不使用 typedef以...结尾的名称_t.所有这些名称都由POSIX保留以供实现使用,并且可以指特定于实现的类型,或者可以在POSIX的未来版本中标准化.不幸的是,许多图书馆作者忽视

我个人不喜欢不typedef用于结构,但如果你选择使用它,至少要避免使用保留的命名空间.

Answer 2

假设我们正在询问下面的代码(typedef在我写这个问题时没有问题,但我认为它应该在那里):

typedef struct someobj {
    // content
} someobj_t;

实际上,通常只需省略名称someobj并使用someobj_t一致就足够了.但是,当您希望结构引用自身时,就是这种情况:

typedef struct someobj {
    struct someobj* next;
    // cannot say someobj_t* yet - typedef not complete
} someobj_t;

// and from now on, both struct someobj and`someobj_t are equivalent