V5/usr/sys/user.h
struct user {
int u_rsav[2]; /* must be first */
int u_fsav[25]; /* must be second */
char u_segflg;
char u_error;
char u_uid;
char u_gid;
char u_ruid;
char u_rgid;
int u_procp;
char *u_base;
char *u_count;
char *u_offset[2];
int *u_cdir;
char u_dbuf[DIRSIZ];
char *u_dirp;
struct {
int u_ino;
char u_name[DIRSIZ];
} u_dent;
int *u_pdir;
int u_uisa[8];
int u_uisd[8];
int u_ofile[NOFILE];
int u_arg[5];
int u_tsize;
int u_dsize;
int u_ssize;
int u_qsav[2];
int u_ssav[2];
int u_signal[NSIG];
int u_utime;
int u_stime;
int u_cutime[2];
int u_cstime[2];
int *u_ar0;
int u_prof[4];
char u_nice;
char u_dsleep;
} u; /* u = 140000 */
/* u_error codes */
#define EFAULT 106
#define EPERM 1
#define ENOENT 2
#define ESRCH 3
#define EIO 5
#define ENXIO 6
#define E2BIG 7
#define ENOEXEC 8
#define EBADF 9
#define ECHILD 10
#define EAGAIN 11
#define ENOMEM 12
#define EACCES 13
#define ENOTBLK 15
#define EBUSY 16
#define EEXIST 17
#define EXDEV 18
#define ENODEV 19
#define ENOTDIR 20
#define EISDIR 21
#define EINVAL 22
#define ENFILE 23
#define EMFILE 24
#define ENOTTY 25
#define ETXTBSY 26
#define EFBIG 27
#define ENOSPC 28
#define ESPIPE 29
#define EROFS 30
#define EMLINK 31