What does this 'elem' means?

[C-SunRay]

wonder what ‘elem’ represents in this‘ I find no declare of this.

[fengxiaohu]

may be it is a linked list of strcut pointer(thread)

[Wangch29]

It means one attribute in struct thread definition, like:

struct thread { tid_t tid; char name[16]; struct list_elem elem; unsigned magic; }

elem means the attribute named "elem" in your struct thread.