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 // <streambuf>
10
11 // template <class charT, class traits = char_traits<charT> >
12 // class basic_streambuf;
13
14 // int_type sgetc();
15
16 #include <streambuf>
17 #include <cassert>
18
19 #include "test_macros.h"
20
21 int underflow_called = 0;
22
23 struct test
24 : public std::basic_streambuf<char>
25 {
26 typedef std::basic_streambuf<char> base;
27
testtest28 test() {}
29
setgtest30 void setg(char* gbeg, char* gnext, char* gend)
31 {
32 base::setg(gbeg, gnext, gend);
33 }
34
35 protected:
underflowtest36 int_type underflow()
37 {
38 ++underflow_called;
39 return 'a';
40 }
41 };
42
main(int,char **)43 int main(int, char**)
44 {
45 {
46 test t;
47 assert(underflow_called == 0);
48 assert(t.sgetc() == 'a');
49 assert(underflow_called == 1);
50 char in[] = "ABC";
51 t.setg(in, in, in+sizeof(in));
52 assert(t.sgetc() == 'A');
53 assert(underflow_called == 1);
54 assert(t.sgetc() == 'A');
55 assert(underflow_called == 1);
56 }
57
58 return 0;
59 }
60