1//===----------------------------------------------------------------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8
9// <fstream>
10
11// pos_type seekoff(off_type off, ios_base::seekdir way,
12// ios_base::openmode which = ios_base::in | ios_base::out);
13// pos_type seekpos(pos_type sp,
14// ios_base::openmode which = ios_base::in | ios_base::out);
15
16#include <fstream>
17#include <cassert>
18
19#include "test_macros.h"
20
21int main(int, char**)
22{
23 {
24 char buf[10];
25 typedef std::filebuf::pos_type pos_type;
26 std::filebuf f;
27 f.pubsetbuf(s: buf, n: sizeof(buf));
28 assert(f.open("seekoff.dat", std::ios_base::in | std::ios_base::out
29 | std::ios_base::trunc) != 0);
30 assert(f.is_open());
31 f.sputn(s: "abcdefghijklmnopqrstuvwxyz", n: 26);
32 LIBCPP_ASSERT(buf[0] == 'v');
33 pos_type p = f.pubseekoff(-15, std::ios_base::cur);
34 assert(p == 11);
35 assert(f.sgetc() == 'l');
36 f.pubseekoff(0, std::ios_base::beg);
37 assert(f.sgetc() == 'a');
38 f.pubseekoff(-1, std::ios_base::end);
39 assert(f.sgetc() == 'z');
40 assert(f.pubseekpos(p) == p);
41 assert(f.sgetc() == 'l');
42 }
43 std::remove(filename: "seekoff.dat");
44
45#ifndef TEST_HAS_NO_WIDE_CHARACTERS
46 {
47 wchar_t buf[10];
48 typedef std::filebuf::pos_type pos_type;
49 std::wfilebuf f;
50 f.pubsetbuf(s: buf, n: sizeof(buf)/sizeof(buf[0]));
51 assert(f.open("seekoff.dat", std::ios_base::in | std::ios_base::out
52 | std::ios_base::trunc) != 0);
53 assert(f.is_open());
54 f.sputn(s: L"abcdefghijklmnopqrstuvwxyz", n: 26);
55 LIBCPP_ASSERT(buf[0] == L'v');
56 pos_type p = f.pubseekoff(-15, std::ios_base::cur);
57 assert(p == 11);
58 assert(f.sgetc() == L'l');
59 f.pubseekoff(0, std::ios_base::beg);
60 assert(f.sgetc() == L'a');
61 f.pubseekoff(-1, std::ios_base::end);
62 assert(f.sgetc() == L'z');
63 assert(f.pubseekpos(p) == p);
64 assert(f.sgetc() == L'l');
65 }
66 std::remove(filename: "seekoff.dat");
67#endif
68
69 return 0;
70}
71

source code of libcxx/test/std/input.output/file.streams/fstreams/filebuf.virtuals/seekoff.pass.cpp