diff --git a/include/fmt/core.h b/include/fmt/core.h
index 6d0bead8..6c9d968b 100644
--- a/include/fmt/core.h
+++ b/include/fmt/core.h
@@ -281,6 +281,12 @@
 #  endif
 #endif
 
+#if defined __cpp_inline_variables && __cpp_inline_variables >= 201606L
+#  define FMT_INLINE_VARIABLE inline
+#else
+#  define FMT_INLINE_VARIABLE
+#endif
+
 // Enable minimal optimizations for more compact code in debug mode.
 FMT_GCC_PRAGMA("GCC push_options")
 #if !defined(__OPTIMIZE__) && !defined(__NVCOMPILER) && !defined(__LCC__)
@@ -2662,7 +2668,7 @@ FMT_CONSTEXPR auto check_char_specs(const format_specs<Char>& specs) -> bool {
   return true;
 }
 
-constexpr int invalid_arg_index = -1;
+constexpr FMT_INLINE_VARIABLE int invalid_arg_index = -1;
 
 #if FMT_USE_NONTYPE_TEMPLATE_ARGS
 template <int N, typename T, typename... Args, typename Char>
diff --git a/include/fmt/format.h b/include/fmt/format.h
index 315644f5..2c4a8b7d 100644
--- a/include/fmt/format.h
+++ b/include/fmt/format.h
@@ -680,7 +680,7 @@ FMT_CONSTEXPR inline auto utf8_decode(const char* s, uint32_t* c, int* e)
   return next;
 }
 
-constexpr uint32_t invalid_code_point = ~uint32_t();
+constexpr FMT_INLINE_VARIABLE uint32_t invalid_code_point = ~uint32_t();
 
 // Invokes f(cp, sv) for every code point cp in s with sv being the string view
 // corresponding to the code point. cp is invalid_code_point on error.