getlogin_r - get login name (thread-safe)

Syntax

#include <unistd.h> int getlogin_r(char * name, size_t namesize);

Description  The getlogin() function writes the user name of the calling process (which corresponds

	to the login name of the calling process) in the data area pointed to by name. The data area is namesize characters long and should be large enough for the name and the terminating null character. The maximum size of the login name is {LOGIN_NAME_MAX}. If getlogin() is successful, then name points to the name that the user logged in under, even if there are several login names with the same user ID.
Return val.	0 Error number		if successful. otherwise.
Errors	The getlogin_r() function fails if:
	ERANGE	The value of namesize is smaller than the length of the login name found including the terminating null character.
See also	getlogin() , getpwnam_r(), getpwuid_r().