linux内核层获取用户名的函数，已经知道用户的uid

Question

在linux的内核层已经知道了用户的uid,怎么获取用户名，用哪个函数？？

Answer 1

struct passwd *getpwuid(uid_t uid);
//man getpwuid

struct passwd {
char pw_name; / username /
char *pw_passwd; / user password /
uid_t pw_uid; / user ID /
gid_t pw_gid; / group ID /
char *pw_gecos; / user information /
char *pw_dir; / home directory /
char *pw_shell; / shell program */
};