# endif /* ! HAVE_ISWCNTRL */
+# if defined __MINGW32__
+
+/* On native Windows, wchar_t is uint16_t, and wint_t is uint32_t.
+ The functions towlower and towupper are implemented in the MSVCRT library
+ to take a wchar_t argument and return a wchar_t result. mingw declares
+ these functions to take a wint_t argument and return a wint_t result.
+ This means that:
+ 1. When the user passes an argument outside the range 0x0000..0xFFFF, the
+ function will look only at the lower 16 bits. This is allowed according
+ to POSIX.
+ 2. The return value is returned in the lower 16 bits of the result register.
+ The upper 16 bits are random: whatever happened to be in that part of the
+ result register. We need to fix this by adding a zero-extend from
+ wchar_t to wint_t after the call. */
+
+static inline wint_t
+rpl_towlower (wint_t wc)
+{
+ return (wint_t) (wchar_t) towlower (wc);
+}
+# define towlower rpl_towlower
+
+static inline wint_t
+rpl_towupper (wint_t wc)
+{
+ return (wint_t) (wchar_t) towupper (wc);
+}
+# define towupper rpl_towupper
+
+# endif
+
#endif /* _GL_WCTYPE_H */
#endif /* _GL_WCTYPE_H */