How to get information of /proc/[pid]/status

Question

Is there a defined structure for getting each field of this file for a particular process instead of parsing the file?

Answer 1

The /proc/pid pseudo-filesystem was created in order to make access to a ton of kernel data accessible to other programs without being tied to binary structures. while /proc/pid/status was designed to

Provides much of the information in /proc/[pid]/stat and /proc/[pid]/statm in a format that's easier for humans to parse. Here's an example:

$ cat /proc/$$/status
Name:   bash
State:  S (sleeping)
Tgid:   3515
Pid:    3515
PPid:   3452
...

This was in contrast to much older mechanisms like stat(2) which required binary structures like

struct stat {
    dev_t     st_dev;     /* ID of device containing file */
    ino_t     st_ino;     /* inode number */
    mode_t    st_mode;    /* protection */
    nlink_t   st_nlink;   /* number of hard links */
    uid_t     st_uid;     /* user ID of owner */
    gid_t     st_gid;     /* group ID of owner */
    dev_t     st_rdev;    /* device ID (if special file) */
    ...
};

If you want a more machine readable version of /proc/pid/status you can use the lexically simpler stat and statm as described in proc(5)