diff --git a/src/corelib/codecs/qtextcodec.cpp b/src/corelib/codecs/qtextcodec.cpp
index 88987865c4..c55f93b949 100644
--- a/src/corelib/codecs/qtextcodec.cpp
+++ b/src/corelib/codecs/qtextcodec.cpp
@@ -993,7 +993,7 @@ QString QTextDecoder::toUnicode(const char *chars, int len)
 }
 
 // in qstring.cpp:
-void qt_from_latin1(ushort *dst, const char *str, size_t size);
+void qt_from_latin1(ushort *dst, const char *str, size_t size) Q_DECL_NOTHROW;
 
 /*! \overload
 
diff --git a/src/corelib/tools/qstring.cpp b/src/corelib/tools/qstring.cpp
index 13d8a3864b..a88b48c767 100644
--- a/src/corelib/tools/qstring.cpp
+++ b/src/corelib/tools/qstring.cpp
@@ -203,7 +203,7 @@ inline RetType UnrollTailLoop<0>::exec(int, RetType returnIfExited, Functor1, Fu
 #endif
 
 // conversion between Latin 1 and UTF-16
-void qt_from_latin1(ushort *dst, const char *str, size_t size)
+void qt_from_latin1(ushort *dst, const char *str, size_t size) Q_DECL_NOTHROW
 {
     /* SIMD:
      * Unpacking with SSE has been shown to improve performance on recent CPUs