Disable nan on platforms without string manip

Author: mborland

include/boost/decimal/detail/cmath/nan.hpp

@@ -11,6 +11,8 @@
 #include <boost/decimal/cstdlib.hpp>
 #include <limits>
 
+#if !defined(BOOST_DECIMAL_DISABLE_CLIB)
+
 namespace boost {
 namespace decimal {
 
@@ -50,4 +52,6 @@ constexpr auto nand128(const char* arg) noexcept -> decimal128
 } //namespace decimal
 } //namespace boost
 
+#endif //#if !defined(BOOST_DECIMAL_DISABLE_CLIB)
+
 #endif //BOOST_DECIMAL_DETAIL_CMATH_NAN_HPP

test/test_cmath.cpp

@@ -1340,13 +1340,15 @@ void test_exp2()
     BOOST_TEST_EQ(exp2(-std::numeric_limits<T>::infinity()), T(0 * dist(rng)));
 }
 
+#if !defined(BOOST_DECIMAL_DISABLE_CLIB)
 template <typename T>
 void test_nan()
 {
     BOOST_TEST(!isnan(nan<T>("1") & std::numeric_limits<T>::quiet_NaN()));
     BOOST_TEST(!isnan(nan<T>("2") & std::numeric_limits<T>::quiet_NaN()));
     BOOST_TEST(!isnan(nan<T>("-1") & std::numeric_limits<T>::quiet_NaN()));
 }
+#endif
 
 int main()
 {
@@ -1456,9 +1458,11 @@ int main()
     test_exp2<decimal32>();
     test_exp2<decimal64>();
 
+    #if !defined(BOOST_DECIMAL_DISABLE_CLIB)
     test_nan<decimal32>();
     test_nan<decimal64>();
     test_nan<decimal128>();
+    #endif
 
     return boost::report_errors();
 }