diff --git a/mingw-w64-headers/crt/sec_api/string_s.h b/mingw-w64-headers/crt/sec_api/string_s.h
index 40eebf62f..1eac92ea1 100644
--- a/mingw-w64-headers/crt/sec_api/string_s.h
+++ b/mingw-w64-headers/crt/sec_api/string_s.h
@@ -60,7 +60,7 @@ extern "C" {
   _CRTIMP errno_t __cdecl _wcsset_s_l(wchar_t *_Str,size_t _SizeInChars,unsigned int _Val,_locale_t _Locale);
   _CRTIMP errno_t __cdecl _wcsnset_s_l(wchar_t *_Str,size_t _SizeInChars,unsigned int _Val, size_t _Count,_locale_t _Locale);
 
-  extern inline size_t __cdecl wcsnlen_s(const wchar_t * _src, size_t _count) {
+  __forceinline size_t __cdecl wcsnlen_s(const wchar_t * _src, size_t _count) {
     return _src ? wcsnlen(_src, _count) : 0;
   }
 #endif
diff --git a/mingw-w64-headers/crt/sec_api/wchar_s.h b/mingw-w64-headers/crt/sec_api/wchar_s.h
index 611f93471..42dd4aee3 100644
--- a/mingw-w64-headers/crt/sec_api/wchar_s.h
+++ b/mingw-w64-headers/crt/sec_api/wchar_s.h
@@ -130,7 +130,7 @@ extern "C" {
   _CRTIMP errno_t __cdecl _wcsset_s_l(wchar_t *_Str,size_t _SizeInChars,unsigned int _Val,_locale_t _Locale);
   _CRTIMP errno_t __cdecl _wcsnset_s_l(wchar_t *_Str,size_t _SizeInChars,unsigned int _Val, size_t _Count,_locale_t _Locale);
 
-  extern inline size_t __cdecl wcsnlen_s(const wchar_t * _src, size_t _count) {
+  __forceinline size_t __cdecl wcsnlen_s(const wchar_t * _src, size_t _count) {
     return _src ? wcsnlen(_src, _count) : 0;
   }
 #endif