Libc-498.tar.gz

[apple/libc.git] / stdio / fflush-fbsd.c

diff --git a/stdio/fflush-fbsd.c b/stdio/fflush-fbsd.c
new file mode 100644 (file)
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--- /dev/null
+++ b/stdio/fflush-fbsd.c
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+/*-
+ * Copyright (c) 1990, 1993
+ *     The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Chris Torek.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *     This product includes software developed by the University of
+ *     California, Berkeley and its contributors.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#if defined(LIBC_SCCS) && !defined(lint)
+static char sccsid[] = "@(#)fflush.c   8.1 (Berkeley) 6/4/93";
+#endif /* LIBC_SCCS and not lint */
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD: src/lib/libc/stdio/fflush.c,v 1.13 2004/07/04 20:17:00 cperciva Exp $");
+
+#include "namespace.h"
+#include <errno.h>
+#include <stdio.h>
+#include <string.h>
+#include "un-namespace.h"
+#include "libc_private.h"
+#include "local.h"
+
+static int     sflush_locked(FILE *);
+
+/*
+ * Flush a single file, or (if fp is NULL) all files.
+ * MT-safe version
+ */
+int
+fflush(FILE *fp)
+{
+       int retval;
+
+       if (fp == NULL)
+               return (_fwalk(sflush_locked));
+       FLOCKFILE(fp);
+
+       /*
+        * There is disagreement about the correct behaviour of fflush()
+        * when passed a file which is not open for reading.  According to
+        * the ISO C standard, the behaviour is undefined.
+        * Under linux, such an fflush returns success and has no effect;
+        * under Windows, such an fflush is documented as behaving instead
+        * as fpurge().
+        * Given that applications may be written with the expectation of
+        * either of these two behaviours, the only safe (non-astonishing)
+        * option is to return EBADF and ask that applications be fixed.
+        */
+       if ((fp->_flags & (__SWR | __SRW)) == 0) {
+               errno = EBADF;
+               retval = EOF;
+       } else
+               retval = __sflush(fp);
+       FUNLOCKFILE(fp);
+       return (retval);
+}
+
+/*
+ * Flush a single file, or (if fp is NULL) all files.
+ * Non-MT-safe version
+ */
+int
+__fflush(FILE *fp)
+{
+       int retval;
+
+       if (fp == NULL)
+               return (_fwalk(sflush_locked));
+       if ((fp->_flags & (__SWR | __SRW)) == 0) {
+               errno = EBADF;
+               retval = EOF;
+       } else
+               retval = __sflush(fp);
+       return (retval);
+}
+
+int
+__sflush(FILE *fp)
+{
+       unsigned char *p;
+       int n, t;
+
+       t = fp->_flags;
+       if ((t & __SWR) == 0)
+               return (0);
+
+       if ((p = fp->_bf._base) == NULL)
+               return (0);
+
+       n = fp->_p - p;         /* write this much */
+
+       /*
+        * Set these immediately to avoid problems with longjmp and to allow
+        * exchange buffering (via setvbuf) in user write function.
+        */
+       fp->_p = p;
+       fp->_w = t & (__SLBF|__SNBF) ? 0 : fp->_bf._size;
+
+       for (; n > 0; n -= t, p += t) {
+               t = _swrite(fp, (char *)p, n);
+               if (t <= 0) {
+                       /* 5340694: reset _p and _w on EAGAIN */
+                       if (t < 0 && errno == EAGAIN) {
+                               if (p > fp->_p) /* some was written */
+                                       memmove(fp->_p, p, n);
+                               fp->_p += n;
+                               if (!(fp->_flags & (__SLBF|__SNBF)))
+                                       fp->_w -= n;
+                       }
+                       fp->_flags |= __SERR;
+                       return (EOF);
+               }
+       }
+       return (0);
+}
+
+static int
+sflush_locked(FILE *fp)
+{
+       int     ret;
+
+       FLOCKFILE(fp);
+       ret = __sflush(fp);
+       FUNLOCKFILE(fp);
+       return (ret);
+}