diff --git a/README.md b/README.md
index 0b57a5b..1327f5a 100644
--- a/README.md
+++ b/README.md
@@ -1,4 +1,8 @@
+
 ## fast_float number parsing library: 4x faster than strtod
+[![Fuzzing Status](https://oss-fuzz-build-logs.storage.googleapis.com/badges/fast_float.svg)](https://bugs.chromium.org/p/oss-fuzz/issues/list?sort=-opened&can=1&q=proj:fast_float)
+[![VS17-CI](https://github.com/fastfloat/fast_float/actions/workflows/vs17-ci.yml/badge.svg)](https://github.com/fastfloat/fast_float/actions/workflows/vs17-ci.yml)
+[![Ubuntu 22.04 CI (GCC 11)](https://github.com/fastfloat/fast_float/actions/workflows/ubuntu22.yml/badge.svg)](https://github.com/fastfloat/fast_float/actions/workflows/ubuntu22.yml)
 
 The fast_float library provides fast header-only implementations for the C++ from_chars
 functions for `float` and `double` types.  These functions convert ASCII strings representing
diff --git a/include/fast_float/ascii_number.h b/include/fast_float/ascii_number.h
index 360ee56..c2a7ea2 100644
--- a/include/fast_float/ascii_number.h
+++ b/include/fast_float/ascii_number.h
@@ -119,7 +119,7 @@ parsed_number_string_t<TCH> parse_number_string(TCH const *p, TCH const * pend,
   answer.valid = false;
   answer.too_many_digits = false;
   answer.negative = (*p == TCH('-'));
-#if FASTFLOAT_ALLOWS_LEADING_PLUS // disabled by default
+#ifdef FASTFLOAT_ALLOWS_LEADING_PLUS // disabled by default
   if ((*p == TCH('-')) || (*p == TCH('+'))) {
 #else
   if (*p == TCH('-')) { // C++17 20.19.3.(7.1) explicitly forbids '+' sign here
diff --git a/include/fast_float/constexpr_feature_detect.h b/include/fast_float/constexpr_feature_detect.h
index 9ec8611..ba8b65c 100644
--- a/include/fast_float/constexpr_feature_detect.h
+++ b/include/fast_float/constexpr_feature_detect.h
@@ -14,13 +14,13 @@
 #define FASTFLOAT_CONSTEXPR14
 #endif
 
-#if __cpp_lib_bit_cast >= 201806L
+#if defined(__cpp_lib_bit_cast) && __cpp_lib_bit_cast >= 201806L
 #define FASTFLOAT_HAS_BIT_CAST 1
 #else
 #define FASTFLOAT_HAS_BIT_CAST 0
 #endif
 
-#if __cpp_lib_is_constant_evaluated >= 201811L
+#if defined(__cpp_lib_is_constant_evaluated) && __cpp_lib_is_constant_evaluated >= 201811L
 #define FASTFLOAT_HAS_IS_CONSTANT_EVALUATED 1
 #else
 #define FASTFLOAT_HAS_IS_CONSTANT_EVALUATED 0
diff --git a/include/fast_float/float_common.h b/include/fast_float/float_common.h
index 704954d..bb45338 100644
--- a/include/fast_float/float_common.h
+++ b/include/fast_float/float_common.h
@@ -482,7 +482,7 @@ void to_float(bool negative, adjusted_mantissa am, T &value) {
 #endif
 }
 
-#if FASTFLOAT_SKIP_WHITE_SPACE // disabled by default
+#ifdef FASTFLOAT_SKIP_WHITE_SPACE // disabled by default
 template <typename = void>
 struct space_lut {
   static constexpr bool value[] = {
diff --git a/include/fast_float/parse_number.h b/include/fast_float/parse_number.h
index da16235..c074c59 100644
--- a/include/fast_float/parse_number.h
+++ b/include/fast_float/parse_number.h
@@ -30,7 +30,7 @@ parse_infnan(TCH const * first, TCH const * last, T &value)  noexcept  {
       minusSign = true;
       ++first;
   }
-#if FASTFLOAT_ALLOWS_LEADING_PLUS // disabled by default
+#ifdef FASTFLOAT_ALLOWS_LEADING_PLUS // disabled by default
   if (*first == TCH('+')) {
       ++first;
   }
@@ -109,7 +109,7 @@ fastfloat_really_inline bool rounds_to_nearest() noexcept {
   //
   // Note: This may fail to be accurate if fast-math has been
   // enabled, as rounding conventions may not apply.
-  #if FASTFLOAT_VISUAL_STUDIO
+  #ifdef FASTFLOAT_VISUAL_STUDIO
   #   pragma warning(push)
   //  todo: is there a VS warning?
   //  see https://stackoverflow.com/questions/46079446/is-there-a-warning-for-floating-point-equality-checking-in-visual-studio-2013
@@ -121,7 +121,7 @@ fastfloat_really_inline bool rounds_to_nearest() noexcept {
   #   pragma GCC diagnostic ignored "-Wfloat-equal"
   #endif
   return (fmini + 1.0f == 1.0f - fmini);
-  #if FASTFLOAT_VISUAL_STUDIO
+  #ifdef FASTFLOAT_VISUAL_STUDIO
   #   pragma warning(pop)
   #elif defined(__clang__)
   #   pragma clang diagnostic pop
@@ -151,7 +151,7 @@ from_chars_result_t<TCH> from_chars_advanced(TCH const * first, TCH const * last
                  std::is_same<TCH, char32_t>::value , "only char, wchar_t, char16_t and char32_t are supported");
 
   from_chars_result_t<TCH> answer;
-#if FASTFLOAT_SKIP_WHITE_SPACE  // disabled by default
+#ifdef FASTFLOAT_SKIP_WHITE_SPACE  // disabled by default
   while ((first != last) && fast_float::is_space(uint8_t(*first))) {
     first++;
   }