changed return type of manipulator

dune/common/std/charconv.hh

@@ -77,9 +77,8 @@ namespace Dune
       {
         std::istringstream s(std::string(first,last));
         s.imbue(std::locale::classic()); // make sure we are in locale "C"
-        auto manipulator_error = manipulator(s);
-        if (manipulator_error)
-          return from_chars_result{first, std::errc{manipulator_error.value()}};
+        if (!manipulator(s))
+          return from_chars_result{first, std::errc::not_supported};
 
         try {
           s >> value; // extract value
@@ -105,9 +104,8 @@ namespace Dune
       {
         std::ostringstream s;
         s.imbue(std::locale::classic()); // make sure we are in locale "C"
-        auto manipulator_error = manipulator(s);
-        if (manipulator_error)
-          return to_chars_result{last, std::errc{manipulator_error.value()}};
+        if (!manipulator(s))
+          return to_chars_result{last, std::errc::not_supported};
 
         // negative integer values in base != 10 are not correctly converted
         bool sign = value < T(0);
@@ -136,10 +134,10 @@ namespace Dune
       std::enable_if_t<std::is_integral<T>::value, int> = 0>
     from_chars_result from_chars (const char* first, const char* last, T& value, int base = 10)
     {
-      return Impl::fromCharsImpl(first, last, value, [base](auto& s) -> std::error_code
+      return Impl::fromCharsImpl(first, last, value, [base](auto& s)
       {
         s >> std::setbase(base);
-        return {};
+        return true;
       });
     }
 
@@ -149,7 +147,7 @@ namespace Dune
     from_chars_result from_chars (const char* first, const char* last, T& value,
                                   chars_format fmt = chars_format::general)
     {
-      return Impl::fromCharsImpl(first, last, value, [fmt](auto& s) -> std::error_code
+      return Impl::fromCharsImpl(first, last, value, [fmt](auto& s)
       {
         if ((int(fmt) & int(chars_format::scientific)) != 0)
           s >> std::scientific;
@@ -157,10 +155,10 @@ namespace Dune
           s >> std::fixed;
         if ((int(fmt) & int(chars_format::hex)) != 0) {
           s >> std::hexfloat;
-          return std::make_error_code(std::errc::not_supported);
-          // Reading hexfloat values not supported by many standard libraries currently
+          return false;
+          // Reading hexfloat values not supported by many standard libraries, currently.
         }
-        return {};
+        return true;
       });
     }
 
@@ -170,10 +168,10 @@ namespace Dune
       std::enable_if_t<std::is_integral<T>::value, int> = 0>
     to_chars_result to_chars (char* first, char* last, T value, int base = 10)
     {
-      return Impl::toCharsImpl(first, last, value, [base](auto& s) -> std::error_code
+      return Impl::toCharsImpl(first, last, value, [base](auto& s)
       {
         s << std::setbase(base);
-        return {};
+        return true;
       });
     }
 
@@ -182,7 +180,7 @@ namespace Dune
       std::enable_if_t<std::is_floating_point<T>::value, int> = 0>
     to_chars_result to_chars (char* first, char* last, T value)
     {
-      return Impl::toCharsImpl(first, last, value, [](auto& /*s*/) -> std::error_code { return {}; });
+      return Impl::toCharsImpl(first, last, value, [](auto& /*s*/) { return true; });
     }
 
     /// \brief Converts a floating-point value to a character sequence with additional format specifier
@@ -190,7 +188,7 @@ namespace Dune
       std::enable_if_t<std::is_floating_point<T>::value, int> = 0>
     to_chars_result to_chars (char* first, char* last, T value, chars_format fmt)
     {
-      return Impl::toCharsImpl(first, last, value, [fmt](auto& s) -> std::error_code
+      return Impl::toCharsImpl(first, last, value, [fmt](auto& s)
       {
         if ((int(fmt) & int(chars_format::scientific)) != 0)
           s << std::scientific;
@@ -198,7 +196,7 @@ namespace Dune
           s << std::fixed;
         if ((int(fmt) & int(chars_format::hex)) != 0)
           s << std::hexfloat;
-        return {};
+        return true;
       });
     }
 
@@ -207,7 +205,7 @@ namespace Dune
       std::enable_if_t<std::is_floating_point<T>::value, int> = 0>
     to_chars_result to_chars (char* first, char* last, T value, chars_format fmt, int precision)
     {
-      return Impl::toCharsImpl(first, last, value, [fmt,precision](auto& s) -> std::error_code
+      return Impl::toCharsImpl(first, last, value, [fmt,precision](auto& s)
       {
         s << std::setprecision(precision);
         if ((int(fmt) & int(chars_format::scientific)) != 0)
@@ -216,7 +214,7 @@ namespace Dune
           s << std::fixed;
         if ((int(fmt) & int(chars_format::hex)) != 0)
           s << std::hexfloat;
-        return {};
+        return true;
       });
     }