1 /*
2  * SPDX-License-Identifier: BSD-3-Clause
3  *
4  * Copyright © 2019 Keith Packard
5  *
6  * Redistribution and use in source and binary forms, with or without
7  * modification, are permitted provided that the following conditions
8  * are met:
9  *
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  *
13  * 2. Redistributions in binary form must reproduce the above
14  *    copyright notice, this list of conditions and the following
15  *    disclaimer in the documentation and/or other materials provided
16  *    with the distribution.
17  *
18  * 3. Neither the name of the copyright holder nor the names of its
19  *    contributors may be used to endorse or promote products derived
20  *    from this software without specific prior written permission.
21  *
22  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
23  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
24  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
25  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
26  * COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
27  * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
28  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
29  * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
31  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
32  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
33  * OF THE POSSIBILITY OF SUCH DAMAGE.
34  */
35 
36 #include <stdio.h>
37 #include <errno.h>
38 
39 #ifndef FSEEK_TYPE
40 #define FSEEK_TYPE long
41 #endif
42 
43 FSEEK_TYPE
ftell(FILE * stream)44 ftell(FILE *stream)
45 {
46         struct __file_ext *xf = (struct __file_ext *) stream;
47         if ((stream->flags & __SEXT) && xf->seek)
48                 return (FSEEK_TYPE) (xf->seek) (stream, 0, SEEK_CUR);
49         errno = ESPIPE;
50 	return -1;
51 }
52