Add S_ISBLK().
diff --git a/Doc/libstat.tex b/Doc/libstat.tex
index a1d8a78..3856723 100644
--- a/Doc/libstat.tex
+++ b/Doc/libstat.tex
@@ -14,13 +14,17 @@
\renewcommand{\indexsubitem}{(in module stat)}
\begin{funcdesc}{S_ISDIR}{mode}
-Return non-zero if the mode was gotten from a directory file.
+Return non-zero if the mode was gotten from a directory.
\end{funcdesc}
\begin{funcdesc}{S_ISCHR}{mode}
Return non-zero if the mode was gotten from a character special device.
\end{funcdesc}
+\begin{funcdesc}{S_ISBLK}{mode}
+Return non-zero if the mode was gotten from a block special device.
+\end{funcdesc}
+
\begin{funcdesc}{S_ISREG}{mode}
Return non-zero if the mode was gotten from a regular file.
\end{funcdesc}