Merge pull request #279 from boostorg/develop

Fix for Debian Build Issue

Author: mborland

include/boost/charconv/detail/config.hpp

@@ -188,4 +188,18 @@ static_assert((BOOST_CHARCONV_ENDIAN_BIG_BYTE || BOOST_CHARCONV_ENDIAN_LITTLE_BY
 #  define BOOST_CHARCONV_HAS_BRAINFLOAT16
 #endif
 
+// Check for PPC64LE with IEEE long double (which is an alias to __float128)
+// See: https://github.com/boostorg/boost/issues/1035
+//
+// IBM128 has 106 Mantissa Digits whereas IEEE128 has 113
+// https://developers.redhat.com/articles/2023/05/16/benefits-fedora-38-long-double-transition-ppc64le#
+#if (defined(__ppc64__) || defined(__PPC64__) || defined(__ppc64le__) || defined(__PPC64LE__)) && (defined(__LONG_DOUBLE_IEEE128__) || LDBL_MANT_DIG == 113)
+
+#define BOOST_CHARCONV_LDBL_IS_FLOAT128
+#define BOOST_CHARCONV_UNSUPPORTED_LONG_DOUBLE
+static_assert(std::is_same<long double, __float128>::value, "__float128 should be an alias to long double. Please open an issue at: https://github.com/boostorg/charconv");
+
+#endif
+
+
 #endif // BOOST_CHARCONV_DETAIL_CONFIG_HPP

src/from_chars.cpp

@@ -229,7 +229,7 @@ boost::charconv::from_chars_result boost::charconv::from_chars_erange(const char
     return r;
 }
 
-#elif !defined(BOOST_CHARCONV_UNSUPPORTED_LONG_DOUBLE)
+#elif !defined(BOOST_CHARCONV_UNSUPPORTED_LONG_DOUBLE) && !defined(BOOST_CHARCONV_LDBL_IS_FLOAT128)
 
 boost::charconv::from_chars_result boost::charconv::from_chars_erange(const char* first, const char* last, long double& value, boost::charconv::chars_format fmt) noexcept
 {

src/to_chars.cpp

@@ -602,7 +602,7 @@ boost::charconv::to_chars_result boost::charconv::to_chars(char* first, char* la
     return boost::charconv::detail::to_chars_float_impl(first, last, static_cast<double>(value), fmt, precision);
 }
 
-#elif !defined(BOOST_CHARCONV_UNSUPPORTED_LONG_DOUBLE)
+#elif !defined(BOOST_CHARCONV_UNSUPPORTED_LONG_DOUBLE) && !defined(BOOST_CHARCONV_LDBL_IS_FLOAT128)
 
 boost::charconv::to_chars_result boost::charconv::to_chars(char* first, char* last, long double value,
                                                            boost::charconv::chars_format fmt) noexcept

src/to_chars_float_impl.hpp

@@ -770,7 +770,7 @@ to_chars_result to_chars_float_impl(char* first, char* last, Real value, chars_f
     return boost::charconv::detail::to_chars_hex(first, last, value, precision);
 }
 
-#if (BOOST_CHARCONV_LDBL_BITS == 80 || BOOST_CHARCONV_LDBL_BITS == 128)
+#if (BOOST_CHARCONV_LDBL_BITS == 80 || BOOST_CHARCONV_LDBL_BITS == 128) && !defined(BOOST_CHARCONV_LDBL_IS_FLOAT128)
 
 template <>
 to_chars_result to_chars_float_impl(char* first, char* last, long double value, chars_format fmt, int precision) noexcept