Add optional 'onerror' argument to os.walk(), to control error

handling.

1 files changed, 9 insertions, 1 deletions

diff --git a/Doc/lib/libos.tex b/Doc/lib/libos.tex
index dd492bbd5f..074d3320a5 100644
--- a/Doc/lib/libos.tex
+++ b/Doc/lib/libos.tex
@@ -1054,7 +1054,8 @@ which is used to set the access and modified times, respectively.
 Availability: Macintosh, \UNIX, Windows.
 \end{funcdesc}
 
-\begin{funcdesc}{walk}{top\optional{, topdown\code{=True}}}
+\begin{funcdesc}{walk}{top\optional{, topdown\code{=True}
+                       \optional{, onerror\code{=None}}}}
 \index{directory!walking}
 \index{directory!traversal}
 \function{walk()} generates the file names in a directory tree, by
@@ -1087,6 +1088,13 @@ about directories the caller creates or renames before it resumes
 false is ineffective, because in bottom-up mode the directories in
 \var{dirnames} are generated before \var{dirnames} itself is generated.
 
+By default errors from the \code{os.listdir()} call are ignored.  If
+optional argument \var{onerror} is specified, it should be a function;
+it will be called with one argument, an os.error instance.  It can
+report the error to continue with the walk, or raise the exception
+to abort the walk.  Note that the filename is available as the
+\code{filename} attribute of the exception object.
+
 \begin{notice}
 If you pass a relative pathname, don't change the current working
 directory between resumptions of \function{walk()}.  \function{walk()}