getlogin(S)                    6 January 1993                    getlogin(S)


 Name

    getlogin - get login name

 Syntax


    cc  . . .  -lc


    char *getlogin ()


 Description

    The getlogin routine returns a pointer to the login name as found in the
    file /etc/utmp.  If getlogin is called within a process that is not
    attached to a terminal, it returns a NULL pointer.

    getlogin may be used in conjunction with the getpwnam routine to locate
    the correct password file entry when the same user ID is shared by
    several login names.

    The correct procedure for determining the login name is to call the
    cuserid or the getlogin routine.  If both fail, one should call the
    getpwuid routine.

 Return value

    Upon successful completion, the getlogin routine returns a pointer to the
    login name.  If the login name is not found or if an error while access-
    ing the /etc/utmp file occurs, getlogin returns the NULL pointer.

 Note

    The return value points to static data whose content is overwritten by
    each call. Therefore, the information should be copied if it needs to be
    saved or used later.

 Files

    /etc/utmp

 See also

    cuserid(S), getgrent(S), getpwent(S), utmp(F)

 Standards conformance

    getlogin conforms with:
    AT&T SVID Issue 2;
    X/Open Portability Guide, Issue 3, 1989;
    IEEE POSIX Std 1003.1-1990 System Application Program Interface (API) [C
    Language] (ISO/IEC 9945-1);
    and NIST FIPS 151-1.