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 // ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_DISABLE_DEPRECATION_WARNINGS -D_LIBCPP_ENABLE_CXX26_REMOVED_STRSTREAM
10 
11 // <strstream>
12 
13 // class strstreambuf
14 
15 // int_type underflow();
16 
17 #include <strstream>
18 #include <cassert>
19 
20 #include "test_macros.h"
21 
22 struct test
23     : public std::strstreambuf
24 {
25     typedef std::strstreambuf base;
testtest26     test(char* gnext_arg, std::streamsize n, char* pbeg_arg = 0)
27         : base(gnext_arg, n, pbeg_arg) {}
testtest28     test(const char* gnext_arg, std::streamsize n)
29         : base(gnext_arg, n) {}
30 
underflowtest31     base::int_type underflow() {return base::underflow();}
32 };
33 
main(int,char **)34 int main(int, char**)
35 {
36     {
37         char buf[10] = "123";
38         test sb(buf, 0, buf + 3);
39         assert(sb.underflow() == '1');
40         assert(sb.underflow() == '1');
41         assert(sb.snextc() == '2');
42         assert(sb.underflow() == '2');
43         assert(sb.underflow() == '2');
44         assert(sb.snextc() == '3');
45         assert(sb.underflow() == '3');
46         assert(sb.underflow() == '3');
47         assert(sb.snextc() == EOF);
48         assert(sb.underflow() == EOF);
49         assert(sb.underflow() == EOF);
50         sb.sputc('4');
51         assert(sb.underflow() == '4');
52         assert(sb.underflow() == '4');
53     }
54 
55   return 0;
56 }
57