diff options
Diffstat (limited to 'newlib/libc/stdio')
| -rw-r--r-- | newlib/libc/stdio/fflush.c | 12 | ||||
| -rw-r--r-- | newlib/libc/stdio/fseek.c | 7 |
2 files changed, 18 insertions, 1 deletions
diff --git a/newlib/libc/stdio/fflush.c b/newlib/libc/stdio/fflush.c index b417e5424..05084dde0 100644 --- a/newlib/libc/stdio/fflush.c +++ b/newlib/libc/stdio/fflush.c @@ -72,8 +72,18 @@ _DEFUN(fflush, (fp), _flockfile (fp); t = fp->_flags; - if ((t & __SWR) == 0 || (p = fp->_bf._base) == NULL) + if ((t & __SWR) == 0) { + /* For a read stream, an fflush causes the next seek to be + unoptimized (i.e. forces a system-level seek). This conforms + to the POSIX and SUSv3 standards. */ + fp->_flags |= __SNPT; + _funlockfile (fp); + return 0; + } + if ((p = fp->_bf._base) == NULL) + { + /* Nothing to flush. */ _funlockfile (fp); return 0; } 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; } |