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 // <ostream>
10
11 // template <class charT, class traits = char_traits<charT> >
12 // class basic_ostream;
13
14 // basic_ostream<charT,traits>& seekp(off_type off, ios_base::seekdir dir);
15
16 #include <ostream>
17 #include <cassert>
18
19 #include "test_macros.h"
20
21 int seekoff_called = 0;
22
23 template <class CharT>
24 struct testbuf
25 : public std::basic_streambuf<CharT>
26 {
27 typedef std::basic_streambuf<CharT> base;
testbuftestbuf28 testbuf() {}
29
30 protected:
31
32 typename base::pos_type
seekofftestbuf33 seekoff(typename base::off_type off, std::ios_base::seekdir way,
34 std::ios_base::openmode which)
35 {
36 ++seekoff_called;
37 assert(way == std::ios_base::beg);
38 assert(which == std::ios_base::out);
39 return off;
40 }
41 };
42
main(int,char **)43 int main(int, char**)
44 {
45 {
46 seekoff_called = 0;
47 std::ostream os((std::streambuf*)0);
48 assert(&os.seekp(5, std::ios_base::beg) == &os);
49 assert(seekoff_called == 0);
50 }
51 {
52 seekoff_called = 0;
53 testbuf<char> sb;
54 std::ostream os(&sb);
55 assert(&os.seekp(10, std::ios_base::beg) == &os);
56 assert(seekoff_called == 1);
57 assert(os.good());
58 assert(&os.seekp(-1, std::ios_base::beg) == &os);
59 assert(seekoff_called == 2);
60 assert(os.fail());
61 }
62 { // See https://bugs.llvm.org/show_bug.cgi?id=21361
63 seekoff_called = 0;
64 testbuf<char> sb;
65 std::ostream os(&sb);
66 os.setstate(std::ios_base::eofbit);
67 assert(&os.seekp(10, std::ios_base::beg) == &os);
68 assert(seekoff_called == 1);
69 assert(os.rdstate() == std::ios_base::eofbit);
70 }
71
72 return 0;
73 }
74