Fix for PPC64 errno value converting LDBL_MIN

include/boost/charconv/to_chars.hpp

@@ -616,12 +616,12 @@
     format[pos] = '\n';
     const auto rv = print_val(first, last - first, format, value);
 
-    if (rv == -1)
+    if (rv <= 0)
     {
         return {last, static_cast<std::errc>(errno)};
     }
 
-    return {first + rv, static_cast<std::errc>(errno)};
+    return {first + rv, std::errc()};
 }
 
 } // Namespace detail

src/from_chars.cpp

@@ -214,7 +214,17 @@
         char* ptr = nullptr;
         value = std::strtold(temp.c_str(), &ptr);
         r.ptr = ptr;
-        r.ec = static_cast<std::errc>(errno);
+
+        // See: https://github.com/cppalliance/charconv/issues/103
+        // The value of errno should be 0 since the conversion is successful, but it is incorrect
+        if (value == 0 || value == HUGE_VALL)
+        {
+            r.ec = static_cast<std::errc>(errno);
+        }
+        else
+        {
+            r.ec = std::errc();
+        }
     }
 
     return r;

test/limits.cpp

@@ -63,6 +63,7 @@ std::ostream& operator<<( std::ostream& os, boost::int128_type v )
 #include <boost/core/lightweight_test.hpp>
 #include <system_error>
 #include <limits>
+#include <string>
 
 void test_odr_use( int const* );
 
@@ -124,24 +125,46 @@ template<typename T> void test_floating_point( T value )
     {
         char buffer[ boost::charconv::limits<T>::max_chars10 ];
         auto r = boost::charconv::to_chars( buffer, buffer + sizeof( buffer ), value );
-        BOOST_TEST(r.ec == std::errc());
+        if (!BOOST_TEST(r.ec == std::errc()))
+        {
+            std::cerr << " Value: " << value
+                      << "\nBuffer: " << std::string(buffer)
+                      << "\n    Ec: " << static_cast<int>(r.ec) << std::endl;
+        }
 
         T v2 = 0;
         auto r2 = boost::charconv::from_chars( buffer, r.ptr, v2 );
 
-        BOOST_TEST(r2.ec == std::errc()) && BOOST_TEST_EQ( v2, value );
+        if (!BOOST_TEST(r2.ec == std::errc()) && BOOST_TEST_EQ( v2, value ))
+        {
+            std::cerr << " Value: " << value
+                      << "\nBuffer: " << std::string(buffer)
+                      << "\nRetVal: " << v2
+                      << "\n    Ec: " << static_cast<int>(r2.ec) << std::endl;
+        }
     }
 
     // no base, max_chars
     {
         char buffer[ boost::charconv::limits<T>::max_chars ];
         auto r = boost::charconv::to_chars( buffer, buffer + sizeof( buffer ), value );
-        BOOST_TEST(r.ec == std::errc());
+        if (!BOOST_TEST(r.ec == std::errc()))
+        {
+            std::cerr << " Value: " << value
+                      << "\nBuffer: " << std::string(buffer)
+                      << "\n    Ec: " << static_cast<int>(r.ec) << std::endl;
+        }
 
         T v2 = 0;
         auto r2 = boost::charconv::from_chars( buffer, r.ptr, v2 );
 
-        BOOST_TEST(r2.ec == std::errc()) && BOOST_TEST_EQ( v2, value );
+        if (!BOOST_TEST(r2.ec == std::errc()) && BOOST_TEST_EQ( v2, value ))
+        {
+            std::cerr << " Value: " << value
+                      << "\nBuffer: " << std::string(buffer)
+                      << "\nRetVal: " << v2
+                      << "\n    Ec: " << static_cast<int>(r2.ec) << std::endl;
+        }
     }
 }
 
@@ -173,17 +196,10 @@ int main()
     test_integral<long long>();
     test_integral<unsigned long long>();
 
-#if !defined(__CYGWIN__) && !defined(__s390x__) && !((defined(__arm__) || defined(__aarch64__))  && !defined(__APPLE__)) && !(defined(__APPLE__) && (__clang_major__ == 12))
-
-    // the stub implementations fail under Cygwin, s390x, linux ARM, and Apple Clang w/Xcode 12.2;
-    // re-enable these when we have real ones
-
     test_floating_point<float>();
     test_floating_point<double>();
     test_floating_point<long double>();
 
-#endif // Broken Platforms
-
 #ifdef BOOST_CHARCONV_HAS_INT128
 
     test_integral<boost::int128_type>();