diff --git a/Doc/lib/libposix.tex b/Doc/lib/libposix.tex
index 1a62bbaa987..467195fb7ac 100644
--- a/Doc/lib/libposix.tex
+++ b/Doc/lib/libposix.tex
@@ -440,10 +440,10 @@ operating system.  The tuple contains 5 strings:
 \var{machine})}.  Some systems truncate the nodename to 8
 characters or to the leading component; a better way to get the
 hostname is \function{socket.gethostname()}%
-\index{gethostname()@\idxcode{gethostname()} (in module socket)}
+\withsubitem{(in module socket)}{\ttindex{gethostname()}}
 or even
 \code{socket.gethostbyaddr(socket.gethostname())}%
-\index{gethostbyaddr()@\idxcode{gethostbyaddr()} (in module socket)}.
+\withsubitem{(in module socket)}{\ttindex{gethostbyaddr()}}.
 (Not on MS-DOS, nor on older \UNIX{} systems.)
 \end{funcdesc}
 
diff --git a/Doc/libposix.tex b/Doc/libposix.tex
index 1a62bbaa987..467195fb7ac 100644
--- a/Doc/libposix.tex
+++ b/Doc/libposix.tex
@@ -440,10 +440,10 @@ operating system.  The tuple contains 5 strings:
 \var{machine})}.  Some systems truncate the nodename to 8
 characters or to the leading component; a better way to get the
 hostname is \function{socket.gethostname()}%
-\index{gethostname()@\idxcode{gethostname()} (in module socket)}
+\withsubitem{(in module socket)}{\ttindex{gethostname()}}
 or even
 \code{socket.gethostbyaddr(socket.gethostname())}%
-\index{gethostbyaddr()@\idxcode{gethostbyaddr()} (in module socket)}.
+\withsubitem{(in module socket)}{\ttindex{gethostbyaddr()}}.
 (Not on MS-DOS, nor on older \UNIX{} systems.)
 \end{funcdesc}