1 files changed, 4 insertions, 0 deletions
diff --git a/newlib/libc/stdio/putc.c b/newlib/libc/stdio/putc.c
index 6a410e216..925341939 100644
--- a/newlib/libc/stdio/putc.c
+++ b/newlib/libc/stdio/putc.c
@@ -84,6 +84,8 @@ _putc_r (struct _reent *ptr,
 {
   int result;
   CHECK_INIT (ptr, fp);
+  if (ORIENT (fp, -1) != -1)
+    return EOF;
   _newlib_flockfile_start (fp);
   result = __sputc_r (ptr, c, fp);
   _newlib_flockfile_end (fp);
@@ -100,6 +102,8 @@ putc (int c,
   struct _reent *reent = _REENT;
 
   CHECK_INIT (reent, fp);
+  if (ORIENT (fp, -1) != -1)
+    return EOF;
   _newlib_flockfile_start (fp);
   result = __sputc_r (reent, c, fp);
   _newlib_flockfile_end (fp);