From 81b8306c5f42de6b2b33fc45db5a0244296d8354 Mon Sep 17 00:00:00 2001
From: Daniel Lemire <daniel@lemire.me>
Date: Mon, 19 May 2025 18:08:36 -0400
Subject: [PATCH] implementation of
 https://www.open-std.org/jtc1/sc22/wg21/docs/papers/2023/p2497r0.html

---
 CMakeLists.txt                    |  2 +-
 include/fast_float/float_common.h |  5 +++++
 tests/CMakeLists.txt              | 21 ++++++---------------
 3 files changed, 12 insertions(+), 16 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 8a1c9a3..fadc27b 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1,4 +1,4 @@
-cmake_minimum_required(VERSION 3.9)
+cmake_minimum_required(VERSION 3.14)
 
 project(fast_float VERSION 8.0.2 LANGUAGES CXX)
 set(FASTFLOAT_CXX_STANDARD 11 CACHE STRING "the C++ standard to use for fastfloat")
diff --git a/include/fast_float/float_common.h b/include/fast_float/float_common.h
index 8fd0560..1d249c5 100644
--- a/include/fast_float/float_common.h
+++ b/include/fast_float/float_common.h
@@ -58,6 +58,11 @@ enum class chars_format : uint64_t {
 template <typename UC> struct from_chars_result_t {
   UC const *ptr;
   std::errc ec;
+
+  // https://www.open-std.org/jtc1/sc22/wg21/docs/papers/2023/p2497r0.html
+  constexpr explicit operator bool() const noexcept {
+    return ec == std::errc();
+  }
 };
 
 using from_chars_result = from_chars_result_t<char>;
diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
index c4e43b2..3ffa8ff 100644
--- a/tests/CMakeLists.txt
+++ b/tests/CMakeLists.txt
@@ -10,7 +10,7 @@ option(FASTFLOAT_SUPPLEMENTAL_TESTS "Run supplemental tests" ON)
 if (NOT SYSTEM_DOCTEST)
   FetchContent_Declare(doctest
     GIT_REPOSITORY https://github.com/onqtam/doctest.git
-    GIT_TAG v2.4.11)
+    GIT_TAG v2.4.12)
 else ()
   find_package(doctest REQUIRED)
 endif()
@@ -23,24 +23,15 @@ endif()
 
 # FetchContent_MakeAvailable() was only introduced in 3.14
 # https://cmake.org/cmake/help/v3.14/release/3.14.html#modules
-# FetchContent_MakeAvailable(doctest)
 if (NOT SYSTEM_DOCTEST)
-  FetchContent_GetProperties(doctest)
-  if(NOT doctest_POPULATED)
-    FetchContent_Populate(doctest)
-    add_subdirectory(${doctest_SOURCE_DIR} ${doctest_BINARY_DIR})
-  endif()
+  FetchContent_MakeAvailable(doctest)
 endif()
 
 add_library(supplemental-data INTERFACE)
 if (FASTFLOAT_SUPPLEMENTAL_TESTS)
-  FetchContent_GetProperties(supplemental_test_files)
-  if(NOT supplemental_test_files_POPULATED)
-    message(STATUS "Supplemental tests enabled. Retrieving test files.")
-    FetchContent_Populate(supplemental_test_files)
-    message(STATUS "Supplemental test files retrieved.")
-    add_subdirectory(${supplemental_test_files_SOURCE_DIR} ${supplemental_test_files_BINARY_DIR})
-  endif()
+  message(STATUS "Supplemental tests enabled. Retrieving test files.")
+  FetchContent_MakeAvailable(supplemental_test_files)
+  message(STATUS "Supplemental test files retrieved.")
   target_compile_definitions(supplemental-data INTERFACE SUPPLEMENTAL_TEST_DATA_DIR="${supplemental_test_files_BINARY_DIR}/data")
 endif()
 
@@ -82,7 +73,7 @@ endif()
 if (FASTFLOAT_SUPPLEMENTAL_TESTS)
   target_compile_definitions(basictest PRIVATE FASTFLOAT_SUPPLEMENTAL_TESTS)
 endif()
-
+fast_float_add_cpp_test(p2497)
 fast_float_add_cpp_test(long_test)
 fast_float_add_cpp_test(powersoffive_hardround)
 fast_float_add_cpp_test(string_test)