1 files changed, 7 insertions, 0 deletions
diff --git a/newlib/libc/stdio/fseek.c b/newlib/libc/stdio/fseek.c
index 2ad98551c..8b189ba17 100644
--- a/newlib/libc/stdio/fseek.c
+++ b/newlib/libc/stdio/fseek.c
@@ -359,6 +359,13 @@ dumb:
   fp->_r = 0;
   /* fp->_w = 0; *//* unnecessary (I think...) */
   fp->_flags &= ~__SEOF;
+  /* Reset no-optimization flag after successful seek.  The
+     no-optimization flag may be set in the case of a read
+     stream that is flushed which by POSIX/SUSv3 standards,
+     means that a corresponding seek must not optimize.  The
+     optimization is then allowed if no subsequent flush
+     is performed.  */
+  fp->_flags &= ~__SNPT;
   _funlockfile (fp);
   return 0;
 }