get.cpp
1.02 KB
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
// Copyright 2016-2022 Antony Polukhin
// Distributed under the Boost Software License, Version 1.0.
// (See the accompanying file LICENSE_1_0.txt
// or a copy at <http://www.boost.org/LICENSE_1_0.txt>.)
//[pfr_example_get
/*`
The following example shows how to access structure fields by index using [funcref boost::pfr::get].
Let's define some structure:
*/
#include <boost/pfr/core.hpp>
struct foo { // defining structure
int some_integer;
char c;
};
/*`
We can access fields of that structure by index:
*/
foo f {777, '!'};
auto& r1 = boost::pfr::get<0>(f); // accessing field with index 0, returns reference to `foo::some_integer`
auto& r2 = boost::pfr::get<1>(f); // accessing field with index 1, returns reference to `foo::c`
//] [/pfr_example_get]
int main() {
if (r1 != 777) return 1;
if (r2 != '!') return 2;
r1 = 42;
r2 = 'A';
if (r1 != 42) return 3;
if (r2 != 'A') return 4;
if (f.some_integer != 42) return 5;
if (f.c != 'A') return 6;
return 0;
}