2 * Copyright (c) 1990, 1993
3 * The Regents of the University of California. All rights reserved.
5 * This code is derived from software contributed to Berkeley by
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 * 3. Neither the name of the University nor the names of its contributors
17 * may be used to endorse or promote products derived from this software
18 * without specific prior written permission.
20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33 #if defined(LIBC_SCCS) && !defined(lint)
34 static char sccsid[] = "@(#)ftell.c 8.2 (Berkeley) 5/4/95";
35 #endif /* LIBC_SCCS and not lint */
36 #include <sys/cdefs.h>
37 __FBSDID("$FreeBSD$");
39 #include "namespace.h"
40 #include <sys/types.h>
45 #include "un-namespace.h"
47 #include "libc_private.h"
50 * standard ftell function.
66 * ftello: return current offset.
75 ret = _ftello(fp, &rv);
79 if (rv < 0) { /* Unspecified value because of ungetc() at 0 */
87 _ftello(FILE *fp, fpos_t *offset)
93 if (fp->_seek == NULL) {
94 errno = ESPIPE; /* historic practice */
99 * Find offset of underlying I/O object, then
100 * adjust for buffered bytes.
102 if (fp->_flags & __SOFF)
105 pos = _sseek(fp, (fpos_t)0, SEEK_CUR);
109 if (fp->_flags & __SRD) {
111 * Reading. Any unread characters (including
112 * those from ungetc) cause the position to be
113 * smaller than that in the underlying object.
115 if ((pos -= (HASUB(fp) ? fp->_ur : fp->_r)) < 0) {
116 fp->_flags |= __SERR;
121 pos -= fp->_r; /* Can be negative at this point. */
122 } else if ((fp->_flags & __SWR) && fp->_p != NULL) {
124 if (fp->_flags & __SAPP)
126 else if (fp->_file != -1 &&
127 (dflags = _fcntl(fp->_file, F_GETFL)) < 0)
129 if ((dflags & O_APPEND) &&
130 (pos = _sseek(fp, (fpos_t)0, SEEK_END)) == -1) {
131 if ((fp->_flags & __SOPT) || __sflush(fp) ||
132 (pos = _sseek(fp, (fpos_t)0, SEEK_CUR)) == -1)
140 * Writing. Any buffered characters cause the
141 * position to be greater than that in the
144 n = fp->_p - fp->_bf._base;
145 if (pos > OFF_MAX - n) {