Merge e6867f54b978ff992f4855ce7026a21c0f1a78b4 into f8c573d7419ab08de382c60005e37caa271e869a

Fixes compilation on GCC/MinGW

README.md

@@ -58,32 +58,36 @@ Example:
 #include "fast_float/fast_float.h"
 #include <iostream>
 #include <string>
+#include <system_error>
 
 int main() {
-  std::string input = "3.1416 xyz ";
+  const std::string input = "3.1416 xyz ";
   double result;
   auto answer = fast_float::from_chars(input.data(), input.data() + input.size(), result);
-  if (answer.ec != std::errc()) { std::cerr << "parsing failure\n"; return EXIT_FAILURE; }
+  if (answer.ec != std::errc()) {
-  std::cout << "parsed the number " << result << std::endl;
+    std::cerr << "parsing failure\n";
+    return EXIT_FAILURE;
+  }
+  std::cout << "parsed the number " << result << '\n';
   return EXIT_SUCCESS;
 }
 ```
 
-Though the C++17 standard has you do a comparison with `std::errc()` to check whether the conversion worked, you can avoid it by casting the result to a `bool` like so:
+Prior to C++26, checking for a successful `std::from_chars` conversion requires comparing the `from_chars_result::ec` member to `std::errc()`. As an extension `fast_float::from_chars` supports the improved C++26 API that allows checking the result by converting it to `bool`, like so:
 
-```cpp
+```C++
 #include "fast_float/fast_float.h"
 #include <iostream>
 #include <string>
 
 int main() {
-  std::string input = "3.1416 xyz ";
+  const std::string input = "3.1416 xyz ";
   double result;
-  if(auto answer = fast_float::from_chars(input.data(), input.data() + input.size(), result)) {
+  if (auto answer = fast_float::from_chars(input.data(), input.data() + input.size(), result)) {
-    std::cout << "parsed the number " << result << std::endl;
+    std::cout << "parsed the number " << result << '\n';
     return EXIT_SUCCESS;
   }
-  std::cerr << "failed to parse " << result << std::endl;
+  std::cerr << "parsing failure\n";
   return EXIT_FAILURE;
 }
 ```
@@ -91,7 +95,7 @@ int main() {
 You can parse delimited numbers:
 
 ```C++
-  std::string input = "234532.3426362,7869234.9823,324562.645";
+  const std::string input = "234532.3426362,7869234.9823,324562.645";
   double result;
   auto answer = fast_float::from_chars(input.data(), input.data() + input.size(), result);
   if (answer.ec != std::errc()) {

include/fast_float/float_common.h

@@ -406,8 +406,8 @@ full_multiplication(uint64_t a, uint64_t b) {
   // But MinGW on ARM64 doesn't have native support for 64-bit multiplications
   answer.high = __umulh(a, b);
   answer.low = a * b;
-#elif defined(FASTFLOAT_32BIT) ||                                              \
+#elif defined(FASTFLOAT_32BIT) || (defined(_WIN64) && !defined(__clang__) &&   \
-    (defined(_WIN64) && !defined(__clang__) && !defined(_M_ARM64))
+                                   !defined(_M_ARM64) && !defined(__GNUC__))
   answer.low = _umul128(a, b, &answer.high); // _umul128 not available on ARM64
 #elif defined(FASTFLOAT_64BIT) && defined(__SIZEOF_INT128__)
   __uint128_t r = ((__uint128_t)a) * b;