--- a/libs/charconv/test/test_float128.cpp
+++ b/libs/charconv/test/test_float128.cpp
@@ -244,8 +244,8 @@ void test_sprintf_float( T value, boost:
 
     char buffer2 [ 256 ] {};
 
-    const char* sprintf_fmt;
-    const char* error_format;
+    const char* sprintf_fmt = "";
+    const char* error_format = "";
     switch (fmt)
     {
         case boost::charconv::chars_format::general:
@@ -575,12 +575,12 @@ void spot_check_inf(const std::string& b
 
 void test_nanq()
 {
-    BOOST_TEST(isnanq(boost::charconv::detail::nanq())) && BOOST_TEST(!issignaling(boost::charconv::detail::nanq()));
+    BOOST_TEST(isnanq(boost::charconv::detail::nanq())) && BOOST_TEST(!boost::charconv::detail::issignaling(boost::charconv::detail::nanq()));
 }
 
 void test_nans()
 {
-    BOOST_TEST(isnanq(boost::charconv::detail::nans())) && BOOST_TEST(issignaling(boost::charconv::detail::nans()));
+    BOOST_TEST(isnanq(boost::charconv::detail::nans())) && BOOST_TEST(boost::charconv::detail::issignaling(boost::charconv::detail::nans()));
 }
 
 #if defined(__GNUC__) && __GNUC__ < 9 && __GNUC__ >= 5
