diff --git a/Doc/lib/libos.tex b/Doc/lib/libos.tex
index e7e1ac5..aa57217 100644
--- a/Doc/lib/libos.tex
+++ b/Doc/lib/libos.tex
@@ -141,7 +141,9 @@
 \begin{funcdesc}{getlogin}{}
 Return the name of the user logged in on the controlling terminal of
 the process.  For most purposes, it is more useful to use the
-environment variable \envvar{LOGNAME} to find out who the user is.
+environment variable \envvar{LOGNAME} to find out who the user is,
+or \code{pwd.getpwuid(os.getuid())[0]} to get the login name
+of the currently effective user ID.
 Availability: \UNIX.
 \end{funcdesc}