getlogin(2)							System Calls Manual						       getlogin(2)

NAME

       getlogin, getlogin_r, setlogin - Gets and sets login name

SYNOPSIS

       #include <unistd.h>

       char *getlogin(void);

       int getlogin_r(
	       char *name,
	       size_t len);

       int setlogin(
	       char *name);

       The following function does not conform to current standards and is supported only for backward compatibility:

       int getlogin_r(char *name, int len);

STANDARDS

       Interfaces documented on this reference page conform to industry standards as follows:

       getlogin(), getlogin_r(): XSH5.0

       Refer to the standards(5) reference page for more information about industry standards and associated tags.

PARAMETERS

       Points to the login name.  Specifies 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.  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 supe-
       ruser, 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.

RETURN VALUES

       Upon  successful  completion, the getlogin() function returns a pointer to a null-terminated string in a static buffer or a null pointer if
       the user's login name cannot be found.  If getlogin() fails, a null pointer is returned, and errno is set to indicate the error.

       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, an error number is returned.

       [Tru64  UNIX]  Upon successful completion, the obsolete version of 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:  [Tru64  UNIX]  The  name
       parameter gave an invalid address.  [Tru64 UNIX]  The name parameter pointed to a string that was too long.

	      [Tru64  UNIX]  Login names are limited to 64 characters, as specified by MAXLOGNAME (which is defined in sys/user.h).  However, this
	      name limit must be enabled in the kernel at boot time by explicitly setting the generic subsystem's login_name_max attribute to  64.
	      For backward compatibility reasons, 12 is the default value of the login_name_max attribute.

       An  additional value for a setlogin() failure is the following: [Tru64 UNIX]   The caller tried to set the login name and was not the supe-
       ruser.

RELATED INFORMATION

       Commands: su(1)

       Functions: setsid(2)

       Standards: standards(5) delim off

																       getlogin(2)