[libcxx-commits] [libcxx] Implement P1885R12: `<text_encoding>` header (PR #141312)

[via libcxx-commits]

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@@ -0,0 +1,49 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include <__config>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+#include <__locale_dir/locale_base_api.h>
+
+#include <text_encoding>
+
+#if __has_include(<langinfo.h>)
+#  include <langinfo.h>
+#endif
+
+#if _LIBCPP_STD_VER >= 26
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+#  if __CHAR_BIT__ == 8
+
+text_encoding text_encoding::environment() {
+  auto __make_locale = [](const char* __name) {
+    text_encoding __enc{};
+    if (auto __loc = __locale::__newlocale(LC_CTYPE_MASK, __name, static_cast<locale_t>(0))) {
+      if (const char* __codeset = nl_langinfo_l(CODESET, __loc)) {
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cor3ntin wrote:

You might want to check that you are in a POSIX environment here. `nl_langinfo_l` is not going to be available on windows, for example

https://github.com/llvm/llvm-project/pull/141312