[libc++][format] Add __format_arg_store.
This implements the struct `__format_arg_store` and its dependencies:
* the class basic_format_arg,
* the class basic_format_args,
* the class basic_format_context,
* the function make_format_args,
* the function wmake_format_args,
* the function visit_format_arg,
* several Standard required typedefs.
The following parts will be implemented in a later patch:
* the child class `basic_format_arg::handle`,
* the function `basic_format_arg::basic_format_arg(const T* p)`.
The following extension has been implemented:
* the class basic_format_arg supports `__[u]int128_t` on platform where libc++ supports 128 bit integrals.
Implements parts of:
* P0645 Text Formatting
Completes:
* LWG3371 visit_format_arg and make_format_args are not hidden friends
* LWG3542 basic_format_arg mishandles basic_string_view with custom traits
Note https://mordante.github.io/blog/2021/06/05/format.html gives a bit more information about the goals and non-goals of this initial patch series.
Reviewed By: #libc, ldionne, vitaut
Differential Revision: https://reviews.llvm.org/D103357
NOKEYCHECK=True
GitOrigin-RevId: 0922ce56f4f04fbcacead6cdf0416341fe44e4bb
diff --git a/include/__availability b/include/__availability
index 13d1195..87d43ed 100644
--- a/include/__availability
+++ b/include/__availability
@@ -139,9 +139,9 @@
// # define _LIBCPP_AVAILABILITY_DISABLE_FTM___cpp_lib_semaphore
// This controls the availability of the C++20 format library.
- // The library is in development and not ABI stable yet. Currently
- // P2216 is aiming to be retroactively accepted in C++20. This paper
- // contains ABI breaking changes.
+ // The library is in development and not ABI stable yet. P2216 is
+ // retroactively accepted in C++20. This paper contains ABI breaking
+ // changes.
# define _LIBCPP_AVAILABILITY_FORMAT
// # define _LIBCPP_AVAILABILITY_DISABLE_FTM___cpp_lib_format
@@ -238,9 +238,9 @@
# endif
// This controls the availability of the C++20 format library.
- // The library is in development and not ABI stable yet. Currently
- // P2216 is aiming to be retroactively accepted in C++20. This paper
- // contains ABI breaking changes.
+ // The library is in development and not ABI stable yet. P2216 is
+ // retroactively accepted in C++20. This paper contains ABI breaking
+ // changes.
# define _LIBCPP_AVAILABILITY_FORMAT \
__attribute__((unavailable))
# define _LIBCPP_AVAILABILITY_DISABLE_FTM___cpp_lib_format