1/* GLIB - Library of useful routines for C programming
2 * Copyright (C) 2021 Iain Lane, Xavier Claessens
3 *
4 * This library is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU Lesser General Public
6 * License as published by the Free Software Foundation; either
7 * version 2.1 of the License, or (at your option) any later version.
8 *
9 * This library is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 * Lesser General Public License for more details.
13 *
14 * You should have received a copy of the GNU Lesser General Public
15 * License along with this library; if not, see <http://www.gnu.org/licenses/>.
16 */
17
18#ifndef __GLIB_TYPEOF_H__
19#define __GLIB_TYPEOF_H__
20
21#if !defined (__GLIB_H_INSIDE__) && !defined (GLIB_COMPILATION)
22#error "Only <glib.h> can be included directly."
23#endif
24
25#include <glib/gversionmacros.h>
26
27/*
28 * We can only use __typeof__ on GCC >= 4.8, and not when compiling C++. Since
29 * __typeof__ is used in a few places in GLib, provide a pre-processor symbol
30 * to factor the check out from callers.
31 *
32 * This symbol is private.
33 */
34#undef glib_typeof
35#if !defined(__cplusplus) && (G_GNUC_CHECK_VERSION(4, 8) || defined(__clang__))
36#define glib_typeof(t) __typeof__ (t)
37#elif defined(__cplusplus) && __cplusplus >= 201103L && GLIB_VERSION_MIN_REQUIRED >= GLIB_VERSION_2_68
38/* C++11 decltype() is close enough for our usage */
39#include <type_traits>
40#define glib_typeof(t) typename std::remove_reference<decltype (t)>::type
41#endif
42
43#endif /* __GLIB_TYPEOF_H__ */
44

source code of include/glib-2.0/glib/glib-typeof.h