Explain what os.read() returns at end of file.

freddrake · freddrake · commit a65375c3e35b · 2002-05-01T03:31:42.000Z
This closes SF bug #550409.  Applying to release21-maint &amp; release22-maint.
diff --git a/Doc/lib/libos.tex b/Doc/lib/libos.tex
@@ -471,7 +471,9 @@ \subsection{File Descriptor Operations \label{os-fd-ops}}
 
 \begin{funcdesc}{read}{fd, n}
 Read at most \var{n} bytes from file descriptor \var{fd}.
-Return a string containing the bytes read.
+Return a string containing the bytes read.  If the end of the file
+referred to by \var{fd} has been reached, an empty string is
+returned.
 Availability: Macintosh, \UNIX, Windows.
 
 Note: this function is intended for low-level I/O and must be applied
