Gets a user's login name.
Standard C Library (libc.a)
include <sys/types.h> include <unistd.h> include <limits.h>
char *getlogin (void)
The getlogin subroutine returns a pointer to the login name in the /etc/utmp file. You can use the getlogin subroutine with the getpwnam (getpwent, getpwuid, getpwnam, putpwent, setpwent, or endpwent Subroutine) subroutine to locate the correct password file entry when the same user ID is shared by several login names.
If the getlogin subroutine cannot find the login name in the /etc/utmp file, it returns the process LOGNAME environment variable. If the getlogin subroutine is called within a process that is not attached to a terminal, it returns the value of the LOGNAME environment variable. If the LOGNAME environment variable does not exist, a null pointer is returned.
The return value can point to static data whose content is overwritten by each call. If the login name is not found, the getlogin subroutine returns a null pointer.
If the getlogin function is unsuccessful, it returns one or more of the following error codes:
| /etc/utmp | Contains a record of users logged into the system. |
The getgrent, getgrgid, getgrnam, putgrent, setgrent, or endgrent (getgrent, getgrgid, getgrnam, setgrent, or endgrent Subroutine) subroutine, getlogin_r (getlogin_r Subroutine) subroutine, getpwent, getpwuid, setpwent, or endpwent (getpwent, getpwuid, getpwnam, putpwent, setpwent, or endpwent Subroutine) subroutine, getpwnam (getpwent, getpwuid, getpwnam, putpwent, setpwent, or endpwent Subroutine) subroutine.
List of Security and Auditing Subroutines, Subroutines Overview in AIX 5L Version 5.2 General Programming Concepts: Writing and Debugging Programs.