Index: include/support/win32/locale_win32.h
===================================================================
--- include/support/win32/locale_win32.h
+++ include/support/win32/locale_win32.h
@@ -95,28 +95,28 @@
 // Locale management functions
 #define freelocale _free_locale
 // FIXME: base currently unused. Needs manual work to construct the new locale
-locale_t newlocale( int mask, const char * locale, locale_t base );
+locale_t newlocale( int __mask, const char * __locale, locale_t __base );
 // uselocale can't be implemented on Windows because Windows allows partial modification
 // of thread-local locale and so _get_current_locale() returns a copy while uselocale does
 // not create any copies.
 // We can still implement raii even without uselocale though.
 
 
-lconv *localeconv_l( locale_t loc );
-size_t mbrlen_l( const char *__restrict s, size_t n,
-                 mbstate_t *__restrict ps, locale_t loc);
-size_t mbsrtowcs_l( wchar_t *__restrict dst, const char **__restrict src,
-                    size_t len, mbstate_t *__restrict ps, locale_t loc );
-size_t wcrtomb_l( char *__restrict s, wchar_t wc, mbstate_t *__restrict ps,
-                  locale_t loc);
-size_t mbrtowc_l( wchar_t *__restrict pwc, const char *__restrict s,
-                  size_t n, mbstate_t *__restrict ps, locale_t loc);
-size_t mbsnrtowcs_l( wchar_t *__restrict dst, const char **__restrict src,
-                     size_t nms, size_t len, mbstate_t *__restrict ps, locale_t loc);
-size_t wcsnrtombs_l( char *__restrict dst, const wchar_t **__restrict src,
-                     size_t nwc, size_t len, mbstate_t *__restrict ps, locale_t loc);
-wint_t btowc_l( int c, locale_t loc );
-int wctob_l( wint_t c, locale_t loc );
+lconv *localeconv_l( locale_t __loc );
+size_t mbrlen_l( const char *__restrict __s, size_t __n,
+                 mbstate_t *__restrict __ps, locale_t __loc);
+size_t mbsrtowcs_l( wchar_t *__restrict __dst, const char **__restrict __src,
+                    size_t __len, mbstate_t *__restrict __ps, locale_t __loc );
+size_t wcrtomb_l( char *__restrict __s, wchar_t __wc, mbstate_t *__restrict __ps,
+                  locale_t __loc);
+size_t mbrtowc_l( wchar_t *__restrict __pwc, const char *__restrict __s,
+                  size_t __n, mbstate_t *__restrict __ps, locale_t __loc);
+size_t mbsnrtowcs_l( wchar_t *__restrict __dst, const char **__restrict __src,
+                     size_t __nms, size_t __len, mbstate_t *__restrict __ps, locale_t __loc);
+size_t wcsnrtombs_l( char *__restrict __dst, const wchar_t **__restrict __src,
+                     size_t __nwc, size_t __len, mbstate_t *__restrict __ps, locale_t __loc);
+wint_t btowc_l( int __c, locale_t __loc );
+int wctob_l( wint_t __c, locale_t __loc );
 
 decltype(MB_CUR_MAX) MB_CUR_MAX_L( locale_t __l );
 
@@ -134,16 +134,16 @@
 #endif
 inline _LIBCPP_INLINE_VISIBILITY
 int
-islower_l(int c, _locale_t loc)
+islower_l(int __c, _locale_t __loc)
 {
- return _islower_l((int)c, loc);
+ return _islower_l((int)__c, __loc);
 }
 
 inline _LIBCPP_INLINE_VISIBILITY
 int
-isupper_l(int c, _locale_t loc)
+isupper_l(int __c, _locale_t __loc)
 {
- return _isupper_l((int)c, loc);
+ return _isupper_l((int)__c, __loc);
 }
 
 #define isdigit_l _isdigit_l
@@ -174,18 +174,18 @@
 #define sprintf_l( __s, __l, __f, ... ) _sprintf_l( __s, __f, __l, __VA_ARGS__ )
 #define vsprintf_l( __s, __l, __f, ... ) _vsprintf_l( __s, __f, __l, __VA_ARGS__ )
 #define vsnprintf_l( __s, __n, __l, __f, ... ) _vsnprintf_l( __s, __n, __f, __l, __VA_ARGS__ )
-_LIBCPP_FUNC_VIS int snprintf_l(char *ret, size_t n, locale_t loc, const char *format, ...);
-_LIBCPP_FUNC_VIS int asprintf_l( char **ret, locale_t loc, const char *format, ... );
-_LIBCPP_FUNC_VIS int vasprintf_l( char **ret, locale_t loc, const char *format, va_list ap );
+_LIBCPP_FUNC_VIS int snprintf_l(char *__ret, size_t __n, locale_t __loc, const char *__format, ...);
+_LIBCPP_FUNC_VIS int asprintf_l( char **__ret, locale_t __loc, const char *__format, ... );
+_LIBCPP_FUNC_VIS int vasprintf_l( char **__ret, locale_t __loc, const char *__format, va_list __ap );
 
 // not-so-pressing FIXME: use locale to determine blank characters
-inline int isblank_l( int c, locale_t /*loc*/ )
+inline int isblank_l( int __c, locale_t /*__loc*/ )
 {
-    return ( c == ' ' || c == '\t' );
+    return ( __c == ' ' || __c == '\t' );
 }
-inline int iswblank_l( wint_t c, locale_t /*loc*/ )
+inline int iswblank_l( wint_t __c, locale_t /*__loc*/ )
 {
-    return ( c == L' ' || c == L'\t' );
+    return ( __c == L' ' || __c == L'\t' );
 }
 
 #endif // _LIBCPP_SUPPORT_WIN32_LOCALE_WIN32_H
Index: src/support/win32/locale_win32.cpp
===================================================================
--- src/support/win32/locale_win32.cpp
+++ src/support/win32/locale_win32.cpp
@@ -16,9 +16,9 @@
 using std::__libcpp_locale_guard;
 
 // FIXME: base currently unused. Needs manual work to construct the new locale
-locale_t newlocale( int mask, const char * locale, locale_t /*base*/ )
+locale_t newlocale( int __mask, const char * __locale, locale_t /*__base*/ )
 {
-    return {_create_locale( LC_ALL, locale ), locale};
+    return {_create_locale( LC_ALL, __locale ), __locale};
 }
 
 decltype(MB_CUR_MAX) MB_CUR_MAX_L( locale_t __l )
@@ -32,90 +32,90 @@
 }
 
 
-lconv *localeconv_l( locale_t loc )
+lconv *localeconv_l( locale_t __loc )
 {
-    __libcpp_locale_guard __current(loc);
+    __libcpp_locale_guard __current(__loc);
     return localeconv();
 }
-size_t mbrlen_l( const char *__restrict s, size_t n,
-                 mbstate_t *__restrict ps, locale_t loc )
+size_t mbrlen_l( const char *__restrict __s, size_t __n,
+                 mbstate_t *__restrict __ps, locale_t __loc )
 {
-    __libcpp_locale_guard __current(loc);
-    return mbrlen( s, n, ps );
+    __libcpp_locale_guard __current(__loc);
+    return mbrlen( __s, __n, __ps );
 }
-size_t mbsrtowcs_l( wchar_t *__restrict dst, const char **__restrict src,
-                    size_t len, mbstate_t *__restrict ps, locale_t loc )
+size_t mbsrtowcs_l( wchar_t *__restrict __dst, const char **__restrict __src,
+                    size_t __len, mbstate_t *__restrict __ps, locale_t __loc )
 {
-    __libcpp_locale_guard __current(loc);
-    return mbsrtowcs( dst, src, len, ps );
+    __libcpp_locale_guard __current(__loc);
+    return mbsrtowcs( __dst, __src, __len, __ps );
 }
-size_t wcrtomb_l( char *__restrict s, wchar_t wc, mbstate_t *__restrict ps,
-                  locale_t loc )
+size_t wcrtomb_l( char *__restrict __s, wchar_t __wc, mbstate_t *__restrict __ps,
+                  locale_t __loc )
 {
-    __libcpp_locale_guard __current(loc);
-    return wcrtomb( s, wc, ps );
+    __libcpp_locale_guard __current(__loc);
+    return wcrtomb( __s, __wc, __ps );
 }
-size_t mbrtowc_l( wchar_t *__restrict pwc, const char *__restrict s,
-                  size_t n, mbstate_t *__restrict ps, locale_t loc )
+size_t mbrtowc_l( wchar_t *__restrict __pwc, const char *__restrict __s,
+                  size_t __n, mbstate_t *__restrict __ps, locale_t __loc )
 {
-    __libcpp_locale_guard __current(loc);
-    return mbrtowc( pwc, s, n, ps );
+    __libcpp_locale_guard __current(__loc);
+    return mbrtowc( __pwc, __s, __n, __ps );
 }
-size_t mbsnrtowcs_l( wchar_t *__restrict dst, const char **__restrict src,
-                     size_t nms, size_t len, mbstate_t *__restrict ps, locale_t loc )
+size_t mbsnrtowcs_l( wchar_t *__restrict __dst, const char **__restrict __src,
+                     size_t __nms, size_t __len, mbstate_t *__restrict __ps, locale_t __loc )
 {
-    __libcpp_locale_guard __current(loc);
-    return mbsnrtowcs( dst, src, nms, len, ps );
+    __libcpp_locale_guard __current(__loc);
+    return mbsnrtowcs( __dst, __src, __nms, __len, __ps );
 }
-size_t wcsnrtombs_l( char *__restrict dst, const wchar_t **__restrict src,
-                     size_t nwc, size_t len, mbstate_t *__restrict ps, locale_t loc )
+size_t wcsnrtombs_l( char *__restrict __dst, const wchar_t **__restrict __src,
+                     size_t __nwc, size_t __len, mbstate_t *__restrict __ps, locale_t __loc )
 {
-    __libcpp_locale_guard __current(loc);
-    return wcsnrtombs( dst, src, nwc, len, ps );
+    __libcpp_locale_guard __current(__loc);
+    return wcsnrtombs( __dst, __src, __nwc, __len, __ps );
 }
-wint_t btowc_l( int c, locale_t loc )
+wint_t btowc_l( int __c, locale_t __loc )
 {
-    __libcpp_locale_guard __current(loc);
-    return btowc( c );
+    __libcpp_locale_guard __current(__loc);
+    return btowc( __c );
 }
-int wctob_l( wint_t c, locale_t loc )
+int wctob_l( wint_t __c, locale_t __loc )
 {
-    __libcpp_locale_guard __current(loc);
-    return wctob( c );
+    __libcpp_locale_guard __current(__loc);
+    return wctob( __c );
 }
 
-int snprintf_l(char *ret, size_t n, locale_t loc, const char *format, ...)
+int snprintf_l(char *__ret, size_t __n, locale_t __loc, const char *__format, ...)
 {
-    __libcpp_locale_guard __current(loc);
+    __libcpp_locale_guard __current(__loc);
     va_list ap;
-    va_start( ap, format );
-    int result = vsnprintf( ret, n, format, ap );
+    va_start( ap, __format );
+    int result = vsnprintf( __ret, __n, __format, ap );
     va_end(ap);
     return result;
 }
 
-int asprintf_l( char **ret, locale_t loc, const char *format, ... )
+int asprintf_l( char **__ret, locale_t __loc, const char *__format, ... )
 {
     va_list ap;
-    va_start( ap, format );
-    int result = vasprintf_l( ret, loc, format, ap );
+    va_start( ap, __format );
+    int result = vasprintf_l( __ret, __loc, __format, ap );
     va_end(ap);
     return result;
 }
-int vasprintf_l( char **ret, locale_t loc, const char *format, va_list ap )
+int vasprintf_l( char **__ret, locale_t __loc, const char *__format, va_list __ap )
 {
-    __libcpp_locale_guard __current(loc);
-    return vasprintf( ret, format, ap );
+    __libcpp_locale_guard __current(__loc);
+    return vasprintf( __ret, __format, __ap );
 }
 
 #if !defined(_LIBCPP_MSVCRT)
-float strtof_l(const char* nptr, char** endptr, locale_t loc) {
-  __libcpp_locale_guard __current(loc);
-  return strtof(nptr, endptr);
+float strtof_l(const char* __nptr, char** __endptr, locale_t __loc) {
+  __libcpp_locale_guard __current(__loc);
+  return strtof(__nptr, __endptr);
 }
 
-long double strtold_l(const char* nptr, char** endptr, locale_t loc) {
-  __libcpp_locale_guard __current(loc);
-  return strtold(nptr, endptr);
+long double strtold_l(const char* __nptr, char** __endptr, locale_t __loc) {
+  __libcpp_locale_guard __current(__loc);
+  return strtold(__nptr, __endptr);
 }
 #endif