fopen: document mingw bug on directories

[gnulib.git] / doc / posix-functions / fopen.texi

diff --git a/doc/posix-functions/fopen.texi b/doc/posix-functions/fopen.texi
index da6acde..442d1b6 100644 (file)
--- a/doc/posix-functions/fopen.texi
+++ b/doc/posix-functions/fopen.texi
@@ -26,4 +26,10 @@ upon failure.
 On Windows, this function returns a file stream in ``text'' mode by default;
 this means that it translates @code{'\n'} to CR/LF by default.  Use the
 @code{"b"} flag if you need reliable binary I/O.
+@item
+On Windows platforms (excluding Cygwin), this function fails to open
+directories for reading.  Such streams have implementation-defined
+semantics on other platforms.  To avoid directory streams with a
+consistent error message, use @code{fstat} after @code{open} and
+@code{fdopen}, rather than @code{fopen} and @code{fileno}.
 @end itemize