1 //===----------------------------------------------------------------------===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is dual licensed under the MIT and the University of Illinois Open
6 // Source Licenses. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 
10 // <string>
11 
12 // const charT& front() const;
13 //       charT& front();
14 
15 #ifdef _LIBCPP_DEBUG
16 #define _LIBCPP_ASSERT(x, m) ((x) ? (void)0 : std::exit(0))
17 #endif
18 
19 #include <string>
20 #include <cassert>
21 
22 #include "min_allocator.h"
23 
24 template <class S>
25 void
test(S s)26 test(S s)
27 {
28     const S& cs = s;
29     assert(&cs.front() == &cs[0]);
30     assert(&s.front() == &s[0]);
31     s.front() = typename S::value_type('z');
32     assert(s.front() == typename S::value_type('z'));
33 }
34 
main()35 int main()
36 {
37     {
38     typedef std::string S;
39     test(S("1"));
40     test(S("1234567890123456789012345678901234567890"));
41     }
42 #if __cplusplus >= 201103L
43     {
44     typedef std::basic_string<char, std::char_traits<char>, min_allocator<char>> S;
45     test(S("1"));
46     test(S("1234567890123456789012345678901234567890"));
47     }
48 #endif
49 #ifdef _LIBCPP_DEBUG
50     {
51         std::string s;
52         char c = s.front();
53         assert(false);
54     }
55 #endif
56 }
57