version.syn#2 requires <string> to define
__cpp_lib_allocator_traits_is_always_equal.
The attached patch therefore defines the
__glibcxx_want_allocator_traits_is_always_equal macro to get the
definition of the feature-test macro from <bits/version.h>.
This is not isolated only to <string> though. The standard requires the
following (as per version.syn#2):
#define __cpp_lib_allocator_traits_is_always_equal 201411L
// freestanding, also in <memory>, <scoped_allocator>, <string>, <deque>,
// <forward_list>, <list>, <vector>, <map>, <set>, <unordered_map>,
// <unordered_set>
After fixing <string>, all the above headers except <memory> still fail to
define the macro. Should similar fixes be created for these headers as well?
Signed-off-by: Dhruv Chawla <dhr...@nvidia.com>
--
Regards,
Dhruv
From 40c0b154f2ef11a18fd318008ae366560d4c8d79 Mon Sep 17 00:00:00 2001
From: Dhruv Chawla <dhr...@nvidia.com>
Date: Mon, 26 Aug 2024 11:09:19 +0530
Subject: [PATCH] libstdc++: Add missing feature-test macro in <string>
version.syn#2 requires <string> to define
__cpp_lib_allocator_traits_is_always_equal.
The attached patch therefore defines the
__glibcxx_want_allocator_traits_is_always_equal macro to get the
definition of the feature-test macro from <bits/version.h>.
This is not isolated only to <string> though. The standard requires the
following (as per version.syn#2):
#define __cpp_lib_allocator_traits_is_always_equal 201411L
// freestanding, also in <memory>, <scoped_allocator>, <string>, <deque>,
// <forward_list>, <list>, <vector>, <map>, <set>, <unordered_map>,
// <unordered_set>
After fixing <string>, all the above headers except <memory> still fail to
define the macro. Should similar fixes be created for these headers as well?
Signed-off-by: Dhruv Chawla <dhr...@nvidia.com>
libstdc++-v3/ChangeLog:
* include/std/string: Define macro
__glibcxx_want_allocator_traits_is_always_equal.
---
libstdc++-v3/include/std/string | 1 +
.../testsuite/21_strings/headers/string/version.cc | 8 ++++++++
2 files changed, 9 insertions(+)
create mode 100644 libstdc++-v3/testsuite/21_strings/headers/string/version.cc
diff --git a/libstdc++-v3/include/std/string b/libstdc++-v3/include/std/string
index 55144409cca..8db0802a282 100644
--- a/libstdc++-v3/include/std/string
+++ b/libstdc++-v3/include/std/string
@@ -54,6 +54,7 @@
#include <bits/basic_string.h>
#include <bits/basic_string.tcc>
+#define __glibcxx_want_allocator_traits_is_always_equal
#define __glibcxx_want_constexpr_char_traits
#define __glibcxx_want_constexpr_string
#define __glibcxx_want_erase_if
diff --git a/libstdc++-v3/testsuite/21_strings/headers/string/version.cc
b/libstdc++-v3/testsuite/21_strings/headers/string/version.cc
new file mode 100644
index 00000000000..a546b75b3fe
--- /dev/null
+++ b/libstdc++-v3/testsuite/21_strings/headers/string/version.cc
@@ -0,0 +1,8 @@
+// { dg-do preprocess { target c++17 } }
+// { dg-add-options no_pch }
+
+#include <string>
+
+#if __cpp_lib_allocator_traits_is_always_equal != 201411L
+# error "Feature-test macro __cpp_lib_allocator_traits_is_always_equal has
wrong value in <version>"
+#endif
--
2.25.1
