Fix constexpr when using libstdc++

include/boost/static_string/config.hpp

@@ -146,10 +146,12 @@ defined(__clang__) && \
 #define BOOST_STATIC_STRING_CPP14_CONSTEXPR
 #endif
 
-// For clang and msvc, constexpr does not work with library
+// These are for compiler/library configurations
-// comparison function objects.
+// that cannot use the library comparison function
-#if (defined(__clang__) && (__clang_major__ < 9)) || \
+// objects at all in constant expresssions. In these
-(defined(_MSVC_LANG) && !defined(BOOST_STATIC_STRING_CPP20))
+// cases, we use whatever will make more constexpr work.
+#if (defined(__clang__) && defined(__GLIBCXX__) && \
+((__GLIBCXX__ > 20181206) && (__GLIBCXX__ < 20190812)))
 #define BOOST_STATIC_STRING_NO_PTR_COMP_FUNCTIONS
 #endif
 
@@ -165,16 +167,6 @@ defined(__clang__) && \
 #include <string_view>
 #endif
 
-#ifdef __clang__
-#include <new>
-#define STRING_VALUE(...) STRING_VALUE__(__VA_ARGS__)
-#define STRING_VALUE__(...) #__VA_ARGS__
-#pragma message("STATIC STRING CLANG DEBUG INFO")
-#pragma message("LIBSTDCXX OLD: " STRING_VALUE(__GLIBCPP__)) 
-#pragma message("LIBSTDCXX NEW: " STRING_VALUE(__GLIBCXX__)) 
-#pragma message("LIBCXX: " STRING_VALUE(_LIBCPP_VERSION)) 
-#endif
-
 namespace boost {
 namespace static_string {
 

include/boost/static_string/static_string.hpp

@@ -509,7 +509,7 @@ to_static_string_float_impl(Floating value) noexcept
 {
   // extra one needed for null terminator
   char buffer[N + 1];
-  std::sprintf(buffer, "%f", value);
+  std::sprintf(buffer, "%Lf", value);
   // this will not throw
   return static_string<N>(buffer);
 }
@@ -521,7 +521,7 @@ to_static_wstring_float_impl(Floating value) noexcept
 {
   // extra one needed for null terminator
   wchar_t buffer[N + 1];
-  std::swprintf(buffer, N + 1, L"%f", value);
+  std::swprintf(buffer, N + 1, L"%Lf", value);
   // this will not throw
   return static_wstring<N>(buffer);
 }
@@ -611,6 +611,9 @@ is_inside(
   // while retaining the guarentee that the comparison has a strict total ordering.
   // We also want this to be fast. Since different compilers have differing levels
   // of conformance, we will settle for the best option that is available.
+  // We don't care about this in C++11, since this function would have
+  // no applications in constant expressions.
+#ifdef BOOST_STATIC_STRING_CPP14
 #ifdef BOOST_STATIC_STRING_NO_PTR_COMP_FUNCTIONS 
 #ifdef BOOST_STATIC_STRING_USE_IS_CONST_EVAL
   // Our second best option is to use is_constant_evaluated
@@ -624,11 +627,12 @@ is_inside(
     return false;
   }
 #else
-  // If library comparison functions don't work, then
+  // If library comparison functions don't work, and
-  // its almost certain that we can use the builtin
+  // we cannot use is_constant_evaluated, we can use
-  // comparison operator instead.
+  // the builtin comparison operators instead.
   return ptr >= src_first && ptr <= src_last;
 #endif
+#endif
 #endif
   // Use the library comparison functions if we can't use 
   // is_constant_evaluated or if we don't need to.