Tested powerpc64le-linux. Pushed to trunk.
-- >8 --
This was just approved in Issaquah.
libstdc++-v3/ChangeLog:
* include/std/format (__format::_Arg_store): New class template.
(basic_format_args): Remove nested type _Store and add deduction
guide from _Arg_store.
(basic_format_arg, make_format_args): Adjust.
* testsuite/std/format/arguments/lwg3810.cc: New test.
---
libstdc++-v3/include/std/format | 101 ++++++++++--------
.../testsuite/std/format/arguments/lwg3810.cc | 25 +++++
2 files changed, 82 insertions(+), 44 deletions(-)
create mode 100644 libstdc++-v3/testsuite/std/format/arguments/lwg3810.cc
diff --git a/libstdc++-v3/include/std/format b/libstdc++-v3/include/std/format
index 1cce4ebd45c..b1e627048de 100644
--- a/libstdc++-v3/include/std/format
+++ b/libstdc++-v3/include/std/format
@@ -2757,6 +2757,10 @@ namespace __format
}
};
+ // [format.arg.store], class template format-arg-store
+ template<typename _Context, typename... _Args>
+ class _Arg_store;
+
} // namespace __format
/// @endcond
@@ -2833,6 +2837,9 @@ namespace __format
template<typename _Ctx>
friend class basic_format_args;
+ template<typename _Ctx, typename... _Args>
+ friend class __format::_Arg_store;
+
static_assert(is_trivially_copyable_v<__format::_Arg_value<_Context>>);
__format::_Arg_value<_Context> _M_val;
@@ -3150,11 +3157,11 @@ namespace __format
static_assert( __format::_Arg_max_ <= (1 << _S_packed_type_bits) );
- // [format.arg.store], class template format-arg-store
- // XXX: Should this be defined outside the class, so basic_format_args
- // can use CTAD with a _Store argument?
template<typename... _Args>
- class _Store;
+ using _Store = __format::_Arg_store<_Context, _Args...>;
+
+ template<typename _Ctx, typename... _Args>
+ friend class __format::_Arg_store;
using uint64_t = __UINT64_TYPE__;
using _Format_arg = basic_format_arg<_Context>;
@@ -3215,52 +3222,60 @@ namespace __format
}
};
+ // _GLIBCXX_RESOLVE_LIB_DEFECTS
+ // 3810. CTAD for std::basic_format_args
+ template<typename _Context, typename... _Args>
+ basic_format_args(__format::_Arg_store<_Context, _Args...>)
+ -> basic_format_args<_Context>;
+
+ template<typename _Context, typename... _Args>
+ auto
+ make_format_args(_Args&&... __fmt_args) noexcept;
+
// An array of type-erased formatting arguments.
- template<typename _Context>
- template<typename... _Args>
- class basic_format_args<_Context>::_Store
- {
- friend class basic_format_args;
+ template<typename _Context, typename... _Args>
+ class __format::_Arg_store
+ {
+ friend std::basic_format_args<_Context>;
- template<typename _Ctx, typename... _Argz>
- friend auto
- make_format_args(_Argz&&...) noexcept;
+ template<typename _Ctx, typename... _Argz>
+ friend auto
+ std::make_format_args(_Argz&&...) noexcept;
- // For a sufficiently small number of arguments we only store values.
- // basic_format_args can get the types from the _Args pack.
- static constexpr bool _S_values_only
- = sizeof...(_Args) <= _S_max_packed_args;
+ // For a sufficiently small number of arguments we only store values.
+ // basic_format_args can get the types from the _Args pack.
+ static constexpr bool _S_values_only
+ = sizeof...(_Args) <= basic_format_args<_Context>::_S_max_packed_args;
- using _Element_t
- = __conditional_t<_S_values_only,
- __format::_Arg_value<_Context>,
- basic_format_arg<_Context>>;
+ using _Element_t
+ = __conditional_t<_S_values_only,
+ __format::_Arg_value<_Context>,
+ basic_format_arg<_Context>>;
- _Element_t _M_args[sizeof...(_Args)];
+ _Element_t _M_args[sizeof...(_Args)];
- template<typename _Tp>
- static _Element_t
- _S_make_elt(_Tp& __v)
- {
- basic_format_arg<_Context> __arg(__v);
- if constexpr (_S_values_only)
- return __arg._M_val;
- else
- return __arg;
- }
+ template<typename _Tp>
+ static _Element_t
+ _S_make_elt(_Tp& __v)
+ {
+ basic_format_arg<_Context> __arg(__v);
+ if constexpr (_S_values_only)
+ return __arg._M_val;
+ else
+ return __arg;
+ }
- template<typename... _Tp>
- requires (sizeof...(_Tp) == sizeof...(_Args))
- [[__gnu__::__always_inline__]]
- _Store(_Tp&... __a) noexcept
- : _M_args{_S_make_elt(__a)...}
- { }
- };
+ template<typename... _Tp>
+ requires (sizeof...(_Tp) == sizeof...(_Args))
+ [[__gnu__::__always_inline__]]
+ _Arg_store(_Tp&... __a) noexcept
+ : _M_args{_S_make_elt(__a)...}
+ { }
+ };
template<typename _Context>
- template<typename... _Args> requires (sizeof...(_Args) == 0)
- class basic_format_args<_Context>::_Store<_Args...>
- { };
+ class __format::_Arg_store<_Context>
+ { };
template<typename _Context>
template<typename... _Args>
@@ -3300,10 +3315,8 @@ namespace __format
inline auto
make_format_args(_Args&&... __fmt_args) noexcept
{
- using _Fmt_args = basic_format_args<_Context>;
using _Fmt_arg = basic_format_arg<_Context>;
- using _Store = typename _Fmt_args::template
- _Store<typename _Fmt_arg::template
+ using _Store = __format::_Arg_store<_Context, typename _Fmt_arg::template
_Normalize<remove_reference_t<_Args>>...>;
return _Store(__fmt_args...);
}
diff --git a/libstdc++-v3/testsuite/std/format/arguments/lwg3810.cc
b/libstdc++-v3/testsuite/std/format/arguments/lwg3810.cc
new file mode 100644
index 00000000000..c1be229040f
--- /dev/null
+++ b/libstdc++-v3/testsuite/std/format/arguments/lwg3810.cc
@@ -0,0 +1,25 @@
+// { dg-do compile { target c++20 } }
+// { dg-options "-std=gnu++20" }
+
+// LWG 3810. CTAD for std::basic_format_args
+
+#include <format>
+
+auto args_store = std::make_format_args(1,2,3);
+std::basic_format_args args = args_store;
+static_assert(std::is_same_v<decltype(args), std::format_args>);
+
+
+template<typename Context>
+void foo(std::basic_format_args<Context>);
+
+void
+test_ctad()
+{
+ using std::basic_format_args;
+ using std::make_format_args;
+ using SomeContext = std::wformat_context;
+
+ // foo(make_format_args<SomeContext>(â¦)); // won't work
+ foo(basic_format_args(make_format_args<SomeContext>(1, 2, 3))); // should
work
+}
--
2.39.2
