Commit 51003d40 authored by Xavier Claessens's avatar Xavier Claessens
Browse files

Use C++11 decltype where possible

There are various places glib uses __typeof__ for type safety, but
that's a GNUC extension. C++11 has standard decltype() that does a
similar job, at least for cases we care about.

This avoids C++ code to always have to cast return value of
g_object_ref() which was causing type kind of error:

error: invalid conversion from ‘gpointer’ {aka ‘void*’} to
‘GstElementFactory*’ {aka ‘_GstElementFactory*’} [-fpermissive]
parent fdc192f4
......@@ -236,6 +236,10 @@
((defined(__GNUC__) && (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 8))) || \
#define glib_typeof(t) __typeof__ (t)
#elif defined(__cplusplus) && __cplusplus >= 201103L
/* C++11 decltype() is close enough for our usage */
#include <type_traits>
#define glib_typeof(t) typename std::remove_reference<decltype (t)>::type
* Copyright 2020 Xavier Claessens
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* Lesser General Public License for more details.
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, see <>.
#include <glib.h>
typedef struct
int dummy;
} MyObject;
static void
test_typeof (void)
#if __cplusplus >= 201103L
// Test that with C++11 we don't get those kind of errors:
// error: invalid conversion from ‘gpointer’ {aka ‘void*’} to ‘MyObject*’ [-fpermissive]
MyObject *obj = g_rc_box_new0 (MyObject);
MyObject *obj2 = g_rc_box_acquire (obj);
g_assert_true (obj2 == obj);
MyObject *obj3 = g_atomic_pointer_get (&obj2);
g_assert_true (obj3 == obj);
MyObject *obj4 = nullptr;
g_atomic_pointer_set (&obj4, obj3);
g_assert_true (obj4 == obj);
MyObject *obj5 = nullptr;
g_atomic_pointer_compare_and_exchange (&obj5, nullptr, obj4);
g_assert_true (obj5 == obj);
MyObject *obj6 = g_steal_pointer (&obj5);
g_assert_true (obj6 == obj);
g_clear_pointer (&obj6, g_rc_box_release);
g_rc_box_release (obj);
g_test_skip ("This test requires C++11 compiler");
main (int argc, char *argv[])
g_test_init (&argc, &argv, NULL);
g_test_add_func ("/C++/typeof", test_typeof);
return g_test_run ();
......@@ -14,6 +14,9 @@ glib_tests = {
'collate' : {},
'cond' : {},
'convert' : {},
'cxx' : {
'source' : ['cxx.cpp'],
'dataset' : {},
'date' : {},
'dir' : {},
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