diff --git a/winsup/cygwin/ChangeLog b/winsup/cygwin/ChangeLog
index b25956a5e..7e201e5d6 100644
--- a/winsup/cygwin/ChangeLog
+++ b/winsup/cygwin/ChangeLog
@@ -1,3 +1,7 @@
+2013-10-23  Corinna Vinschen  <corinna@vinschen.de>
+
+	* include /cygwin/config.h (_READ_WRITE_BUFSIZE_TYPE): Define.
+
 2013-10-23  Corinna Vinschen  <corinna@vinschen.de>
 
 	* fhandler.cc (fhandler_base::fstat): Drop FH_FULL case to align
diff --git a/winsup/cygwin/include/cygwin/config.h b/winsup/cygwin/include/cygwin/config.h
index cd73388d5..3bea0ecb1 100644
--- a/winsup/cygwin/include/cygwin/config.h
+++ b/winsup/cygwin/include/cygwin/config.h
@@ -69,6 +69,7 @@ extern char *_tlsbase __asm__ ("%fs:4");
    Cygwin.  Changing them in applications has no or not the desired effect.
    Just leave them alone. */
 #define _READ_WRITE_RETURN_TYPE _ssize_t
+#define _READ_WRITE_BUFSIZE_TYPE size_t
 #define __LARGE64_FILES 1
 #define __USE_INTERNAL_STAT64 1
 #define __LINUX_ERRNO_EXTENSIONS__ 1