2007-03-15 Jeff Johnston <jjohnstn@redhat.com>

        * configure.in: Add new --enable-newlib-reent-small option.
        * configure: Regenerated.
        * acconfig.h: Add _WANT_REENT_SMALL.
        * newlib.hin: Regenerated minus PACKAGE macros to add
        _WANT_REENT_SMALL macro.
        * libc/include/sys/config.h[_WANT_REENT_SMALL]: Set _REENT_SMALL
        if not already set.
        * libc/stdio/fflush.c[_REENT_SMALL]: Return immediately if
        there is no buffer.
        * libc/stdio/local.h[_REENT_SMALL]: Fix CHECK_INIT macro to
        use reentrant pointer passed in when resetting the file
        pointer to one of the std streams.

1 files changed, 16 insertions, 0 deletions

diff --git a/newlib/libc/stdio/fflush.c b/newlib/libc/stdio/fflush.c
index a8ef755c2..d46b41f94 100644
--- a/newlib/libc/stdio/fflush.c
+++ b/newlib/libc/stdio/fflush.c
@@ -67,6 +67,22 @@ _DEFUN(fflush, (fp),
   if (fp == NULL)
     return _fwalk (_GLOBAL_REENT, fflush);
 
+#ifdef _REENT_SMALL
+  /* For REENT_SMALL platforms, it is possible we are being
+     called for the first time on a std stream.  This std
+     stream can belong to a reentrant struct that is not
+     _REENT.  If CHECK_INIT gets called below based on _REENT,
+     we will end up changing said file pointers to the equivalent
+     std stream off of _REENT.  This causes unexpected behavior if
+     there is any data to flush on the _REENT std stream.  There
+     are two alternatives to fix this:  1) make a reentrant fflush
+     or 2) simply recognize that this file has nothing to flush
+     and return immediately before performing a CHECK_INIT.  Choice
+     2 is implemented here due to its simplicity.  */
+  if (fp->_bf._base == NULL)
+    return 0;
+#endif /* _REENT_SMALL  */
+
   CHECK_INIT (_REENT, fp);
 
   _flockfile (fp);