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     PW_MAPPING(S)             UNIX System V             PW_MAPPING(S)



     Name
          pw_mapping: pw_nametoid, pw_idtoname, gr_nametoid,
          gr_idtoname - map between user and group names and IDs

     Syntax
          int pw_nametoid(name)
          char *name;

          char *pw_idtoname(id)
          int id;

          int gr_nametoid(name)
          char *name;

          char *gr_idtoname(id)
          int id;

     Description.
          These routines provide an efficient mapping between user and
          group names and identifiers (IDs).  They maintain a separate
          binary database, which is automatically updated each time
          the routines encounter a changed /etc/passwd or /etc/group
          file.  Also, these routines do not interfere with the
          behavior of the getpwent(S) and getgrent(S) routines, and
          are thus used by the Protected Database routines, which must
          frequently convert between names and identifiers but may not
          disrupt an application's use of password mapping routines.

          These routines are much more efficient than the getpwent(S)
          and getgrent(S) routines, in that they do not parse the
          underlying files and keep the database in memory after the
          first use.  Thus, savings are much greater for the second
          and subsequent lookups.  The binary databases are stored in
          the /etc/auth/system directory, which is maintained by the
          Auth protected subsystem.

     Diagnostics
          Routines returning character strings return NULL on failure,
          and a pointer to a string in an internal (to the routines)
          memory area containing the user or group name on success.
          Routines returning integers return a non-negative user or
          group ID on success, or a -1 on failure.

     See Also
          getpwent(S), getgrent(S), getprpwent(S)

     Files
          /etc/auth/system/pw_id_map
          /etc/auth/system/gr_id_map
          /etc/passwd
          /etc/group

     Notes
          Programs using these routines must be linked with -lprot.


                                             (printed 6/20/89)