pw_nametoid(S)                 6 January 1993                 pw_nametoid(S)


 Name

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

 Syntax


    cc  . . .  -lprot


    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 con-
    vert between names and identifiers but may not disrupt an application's
    use of password mapping routines.

    The pwnametoid expects the character argument name, a user name, and
    returns its associated user ID. The pwidtoname expects the argument id,
    a user ID number, and returns its associated user name.

    The grnametoid expects the character argument name, a group name, and
    returns its associated group ID. The gridtoname expects the argument id,
    a group ID number, and returns its associated group name.

    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.

 Return value

    Upon successful completion, the pwidtoname and the gridtoname routines
    return a pointer to a string in an internal (to the routines) memory area
    containing the user or the group names.  These routines return a NULL on
    failure.

    Upon successful completion, the pwnametoid and the grnametoid routines
    return a non-negative user or group ID. On failure, these routines return
    a value of -1.

 Files

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

 See also

    getpwent(S), getgrent(S), getprpwent(S)

 Standards conformance

    All of these routines are an extension of AT&T System V provided by the
    Santa Cruz Operation.