atof() description: Add information about accepting 'NaN' to produce
the NaN value.
diff --git a/Doc/lib/libstring.tex b/Doc/lib/libstring.tex
index 4424863..56dcf6d 100644
--- a/Doc/lib/libstring.tex
+++ b/Doc/lib/libstring.tex
@@ -59,9 +59,11 @@
\begin{funcdesc}{atof}{s}
Convert a string to a floating point number. The string must have
the standard syntax for a floating point literal in Python,
- optionally preceded by a sign (\samp{+} or \samp{-}). Note that
- this behaves identical to the built-in function
- \function{float()}\bifuncindex{float} when passed a string.
+ optionally preceded by a sign (\samp{+} or \samp{-}), or be
+ \code{'NaN'} (case insensitive) to indicate the IEEE ``Not a
+ Number'' value. Note that this behaves identical to the built-in
+ function \function{float()}\bifuncindex{float} when passed a
+ string.
\end{funcdesc}
\begin{funcdesc}{atoi}{s\optional{, base}}