On AIX and Windows platforms, @code{wchar_t} is a 16-bit type and therefore cannot
accommodate all Unicode characters.
@item
+When formatting an integer with grouping flag, this function inserts thousands
+separators even in the "C" locale on some platforms:
+NetBSD 5.1.
+@item
On some platforms, this function does not set @code{errno} or the
stream error indicator on attempts to write to a read-only stream:
Cygwin 1.7.9.