NAME

getlogin, getlogin_r, setlogin − Gets and sets login name

SYNOPSIS

#include <unistd.h> char ∗getlogin( void ); int getlogin_r(
char ∗name,
int len ); setlogin (
char ∗name );

PARAMETERS

namePoints to the login name. 

lenSpecifies the length of the buffer pointed to by name. 

DESCRIPTION

The getlogin() function returns the login name of the user associated with the current session, as previously set by the setlogin() function.  The name is normally associated with a login shell at the time a session is created, and is inherited by all processes descended from the login shell.  (This is true even if some of those processes assume another user ID, for example when the su command is used.) 

The setlogin() function sets the login name of the user associated with the current session to name.  This call is restricted to the superuser, and is normally used only when a new session is being created on behalf of the named user (for example, at login time, or when a remote shell is invoked). 

The getlogin_r() function is the reentrant version of getlogin().  Upon successful completion, the login name is stored in name. 

NOTES

AES Support Level:
Full use (getlogin())

RETURN VALUES

Upon successful completion, the getlogin() function returns a pointer to a null-terminated string in a static buffer.  If the name has not been set, it returns null. 

Upon successful completion, the setlogin() function returns a value of 0 (zero).  If setlogin() fails, then a value of −1 is returned and an error code is placed in errno. 

Upon successful completion, the getlogin_r() function returns a value of 0 (zero).  Otherwise, -1 is returned and errno is set to indicate the error. 

ERRORS

If the getlogin(), getlogin_r(), or setlogin() function fails, errno may be set to one of the following values:

[EFAULT]The name parameter gave an invalid address. 

[EINVAL]The name parameter pointed to a string that was too long.  Login names are limited to MAXLOGNAME characters (defined in sys/user.h). 

[EPERM]The caller tried to set the login name and was not the superuser. 

RELATED INFORMATION

Functions: setsid(2)

Command: su(1)